If you have not already seen this long running thread on Thermador, you might find some useful information in it:

http://ths.gardenweb.com/discussions/2325529/any-positive-thermador-reviews

More generally, the term "high end" ranges can cover a lot of ground because premium priced stoves come in different styles and set-ups. Often, when folks are discussing "high-end ranges, the discussion focuses on the "pro-style" segment of the market, but that is a particular market segment. As Corie Hall points out, there are other, differently styled
and configurations of high-end ranges such as the French-made
LaCanche.

Whether they are "worth it" is something discussed in previous threads which you might want to check out if you have not already seen them. Examples are this thread from gardenweb and this one from chowhound

As for high end stoves being less reliable, that is hard to gauge. Real data is just plain hard to come by. The sales volumes are much lower than for major brands, and the support services can be much more limited than with major brands. With smaller production runs, OEM replacement parts can be pretty expensive. (With simpler pro-style stoves, though, you may well be able to find generic replacements at a much lower cost.) There is nothing like poor warranty service and support to turn a disappointed customer into a vitriolically hateful internet crusader when it comes to buyers of high volume major brand appliances. That aspect of the problem gets magnified when you've shelled out twice as much (or more) to buy a premium priced boutique appliance that goes south on you.

Your comment about your BMW's repair record brings to mind Viking which pretty much poisoned the well for discussing the reliability and durability of pro-style appliances. The company more or less created the market for pro-style appliances and had a very large share of that market. It also had some major quality control problems. Back in 2007, before the recession, Consumer Reports membership surveys were showing that one-in-three members who bought VIking gas ranges had major failures with the first few years of ownership. (2007 was the last year for which CR had data because the sales volume dropped off pretty dramatically when the recession started in 2008 and VIking has since been sold to the Middleby group.) Judging by posts here, Dacor has or has had significant problems with the electronics boards in its dual fuel stoves. They are not alone in that, of course, CR's membership surveys are indicating similar problem rates with the electronics in JennAir and Kitchenaid ranges. Wolf/Subzero's dual-fuel ranges have had enough problems with the ovenlinings cracking that there is now a class action lawsuit. That case might tells us how wide spread the problem is. The fact of the litigation does not tell us that Wlof/Subzero is or is not significantly more problem prone than major brand appliances. There is also litigation with major brand appliance makers, as well. For example, there is a class action lawsuit against Whirlpool over fires started by circuit boards in Whirlpool, Kitchenaid and Maytag dishwashers.

As for choosing between the Blue Star and Thermador, you could look at this thread from last year.

As for choosing between that Frigidaire and the pro-style ranges, one thing that can be considered is that prostyle ranges typically have wider burner spacing. The standard spacing on major brands will be 9" on center, front to back. On pro-style ranges, like the Blue Star, the spacing will be 11" on center, front to back. That spacing makes it easier to run four large pots at a time, say a couple of large stockpots in the back and a couple of 12" skillets up front. If you do not do much of that kind of cooking, this will be a matter of indifference to you.

OTOH, that Thermador model, the PRD305PH, has five burners. Some folks here really like five burner layouts on 30" ranges; others hate them. Also, the Thermador has an 18K btu burner on the right front and a 15k btu burner in the center. If you want to use two big pans at the same time (say a big stockpot and a wide dutch oven) you might have problems fitting them together onto the cooktop at the same time. Maybe you do this kind of cooking and that matters, maybe you do not and it will not matter to you.

If you can, take some of your frequently used pans down to the store to
see how well they fit together for you on the Thermador, the Blue
Star and, if you can, the Frigidaire. That may tell you as
much or more than twenty comments here. After all, it is your
preferences that count.

A few more random comments on things to weigh and consider. (Some of these thoughts might have been covered in the threads I linked to above.)

The Blue Star has a pretty industrial look with a cast iron stovetop. You may find that look a matter of indifference, you might find it attractive, you might find it appalling. Best figure that out before spending $3.3k on a stove.

You mentioned oven sizes. The BS has one of the largest (if not the largest) oven you can get on a 30" range in North America. It will hold a full sheet pan which is something few of us have or use. However, lots of us have half-sheet pans and similarly sized cookie sheets. You can put them longways in and get numbers of them together in the BS oven. The Frigidaire and Thermador ovens virtually the same size, which is noticably smaller and shallower than the BS oven. This might or might not matter to you depending on how and what you bake and roast, and how much of it you do.

If you want deeper and larger ovens in the Frigidaire's price range, you might want to look at dual fuel ranges in GE Profile line. IIRC, some of GE's DF ranges also now have a full power convection element in the oven much as the Thermador does. Could be nice if you do a lot of baking a roasting.

Consider ease/difficulty of cleaning. The Frigidaire and Thermador both have high heat oven self-cleaning. That will be anathema to some because of fears (not unfounded) that high-heat cleaning cycles can degrade a stove's electronic control boards leading to failures and expensive repairs in some unknown portion of the product line. (This is more a matter of uncertainty than a definable risk -- we stove-buyers know it will happen with some stoves in any model line but not what proportion of them or when.)

There is a certain neo-luddite appeal to the simplicity of the Blue Star oven.

The Frigidaire and Thermador both have (I believe) enameled stove tops around the burners. Depending on how deep the wells around the burners are, they may or may not quickly bake on gunk from the spatters, spills and boilovers of daily cooking. Standard design shallow wells do this faster and are harder to clean than deeper wells. I'm contrasting my former GE Dual Fuel range (painted top with shallow wells that required constant attention) with my current pro-style NXR (deep wells that I mostly just wipe out with a microfiber cloth.) If you have not seen this before, here is a video from EuroStoves on cleaning the top of the Blue Star.

thanks both of you for your replies. Especially jwvideo. There is a lot of info in there. Still need to follow the links to read up more. Just as a FYI. I'm not looking at a Frigidaire range just saying other than the minor annoyance with the top and cleaning gunk off of the glass top it was a fine range. Well that and because of the design of the oven, you could see water drips in the middle of the oven window where you couldn't clean unless you tore the door apart. My mother bought one two but she wanted induction top and complained loudly about it. It didn't bother me all that much.

Anyways the cheaper range i'm considering is:

http://www.lowes.com/pd/Samsung-5-Burner-5-8-cu-ft-Slide-In-Convection-Gas-Range-Stainless-Steel-Common-30-in-Actual-29-8125-in/50266969

While, of course it isn't as sturdily built or look as nice, its still not a bad looking stove.

Oh yes and if i go with a blue star i think after research i like the open burner design better so i would probably go with the RCS304BV2

Well now i'm leaning towards the bluestar RCS304BV2 to be honest. Not meaning i won't change my mind. Decisions i hate it :). Why? After researching their open burners i absolutely love them. It has an huge oven which i also love. I won't get a self cleaning (high heat) oven which lots of people here recommend against anyway. Also i will have to go down 3k in btu from the thermador (which i'm doubting) i would be able to notice especially with wok cooking where i would really need it. The wok is would be essentially on top of the burner which should help reduce the 3k btu difference.

I was a little worried about a gas oven (no dual fuel) because of the unevenness of some gas ovens but i'm sure with a high end brand like bluestar that i won't have to worry. I would like to have the 22k burner but that would be way beyond my budget.

Just to let you know, I too was worried about using a gas oven instead of electric. We purchased a BlueStar RNB earlier this year and have had no problems with the gas oven at all. I kept having nightmarish thoughts about ruined meals and burnt cookies but everything (cakes, meats, cookies and even the kids' frozen pizzas) have come out beautifully. So I would not be worried about the switch from electric to gas as far as the oven is concerned. We love our BS range (we were going back and forth between Wolf and BS) and would buy the same one again.

I have a BS RCS and I love it. The open burners are fantastic, put out a lot of heat, are easy to clean and a joy to cook on. I've had my RCS for almost 1 1/2 yrs now and I would get it again.

I wanted the RNB but it was out of our price range and I thought the 15K burners might be a bit underpowered for what I was hoping for with a new range. They are not. I do not sear steak, but fish and chicken come out wonderfully, stir frying is fantastic, as are sautéing and simmering. Except for stir frying, I always have to turn the heat down during the cooking process or things will burn.

I've always had a gas oven and never had an issue baking anything. I now have a speed oven along w/my gas oven, my first electric oven!! and I love it for many things but I wouldn't say that food turns out better baked in it. The speed oven is wonderful for many reasons I won't get into here, but you will find baking in a gas oven is nothing to be concerned about, as mandy_elaine so eloquently said.