I have a GE free standing that is about 10 years old and it has convection. I would say what ever you do, be sure to get one with convection bake.

Here's a better comparison list, there is also a GE PS968 that is a step above the PS905.

Here is a link that might be useful: http://www.ajmadison.com/product/compare/?skus[]=PS968&skus[]=PS905&skus[]=JSP42DN&skus[]=JSP46DP

"4.4 vs 4.1 cubic ft in the oven: is this a significant difference?"
No.

"How much do I REALLY care about the # of racks and positions?"
Dunno. Seems like you've answered your own question. If you do not care, you do not care. Personally, I make use of the three racks and the flexible arrangements that the oven in my GE stove gives me, I do the kind of entertaining and baking where those features have proved useful --- for example, running mass quantities of baked goods through the overn, heating potluck dishes, etc.

"-Warming zone...is there any point to this?"
Not for me. Somebody must like them and I see that GE is putting them on several stoves.

"-Convection: * * *don't want to learn a new way to cook. Would it be foolish to not get it in case I change my mind in the future?"

You do not need to learn a new way to cook. I find that some things just cook a bit faster (using convection may shave half an hour off turkey roasting times for me.) Some things may wind up looking a bit better with less need for my intervention. It also helps some when, say, I want to brown the tops of biscuits, for which I turn on the convection "raost" function.

IIRC, the current GE ranges' over controllers can adjust temperature down for you, if you want. I've never really found that necessary, but ymmv. Persoanly, I like convection for breads, cookies, and roasted meats and veggies, and anytime when I have large quantities in my GE stove's oven. That said, there is no one-size-fits-all answer. That is why you can search here on "convection" and find all kinds of opinions. If it does not make any difference in price, you might as well get it.

"Hidden bake: I've heard mixed thoughts but it seems like something I would want so that ooey gooey food doesn't drip on the heating element."

The trade-off with the hidden-element flat-floor is that the oven takes a few minutes longer to pre-heat. That really bothers some people and does not matter to others. I'm in the latter category, myself, and would like to have one just because it is easier to keep the oven clean.

"Bridge element: *** I can still use each burner separately without it, right?"

Yup.

"Oh, and the appliance guy told me that even if I got convection, I could still use the oven on the regular setting. That's true, right?"

Yup.

The glass ceramic top doesn't matter, it's all the same. Just pick the pattern you like.

The warming thing is one of those take-it-or-leave-it deals for me. You can't cook with it, but if you have a 5th pot of something that you need to keep warm while doing something else, it's useful for that.

I wouldn't have an oven without convection. Period.

Hidden element bothers me because of how much time it takes to heat up and regulate that heat. Anything dripped will still stick and burn. And you CANNOT put anything on it to protect it, like an oven liner or foil.

Bridge element I might use if I had an oblong pan. Not a must-have.

On stick and burn, I'm not sure there will be much difference between what sticks and burns over top of the hidden element and what sticks and burns on the floor around the exposed bake element if the spill sits on the floor for any length of time. It just strikes me as easier to scoop something (or most of something) off an oven floor with the element under the floor than it is to scrape that same stuff where I have to navigate around the bake element to get it. (I might add that I have the exposed element in my oven, so I'm not opposed to them). Once stuff burns on, you have to resort to oven cleaning whichever set-up you choose.

As weedmeister emphasizes, you really cannot put a liner on the bottom floor of a hidden electric bake element. (Well, I suppose you could put some quarry tile on it for some kinds of baking where you can wait a really long time for the oven to come to heat.) And there is no getting round the hidden electric bake elements taking longer to bring the oven to full heat.

Not sure about the effect on regulating heat. For one thing, "regulating" can mean different things to different folks. If you want to rapidly adjust from low to high heat, there is going to be some lag with a hidden element just as there is when pre-heating. But if you are looking for evenness of heating, that may be harder to generalize about. If I recall correctly, one of Consumer Reports evaluations tries to identify evenness of heating when baking. They basically bake sheets of sugar cookies and somehow measure the evenness of browning. Some hidden bake elements do pretty well in that department and some exposed element ovens do not. A third way to look at regulating is how well or how quickly the oven comes back to heat after you've opened the door to check or rotate something. When you add in convection, it may even things out more, as well. Or not. Depends on the model of the .stove That is is why I said I find it hard to generalize about this aspect.

I am sure that I have seen discussion of these points before but the search engine is giving me no hits right now.

With an exposed element, you can put an oven-liner tray or aluminum foil under the element. If something spills and burns, you can slip out the tray/foil and slap in a new one when every thing cools in about 30 seconds. With a hidden element, you cannot use a tray/foil so everything burns onto the bottom. You're stuck with self-cleaning or EasyOff.

Hidden element ovens are slightly larger cubic-inch wise.

Funny, I thought the Hidden Element was going to be a good thing. Now it sounds like it takes (significantly) longer to pre-heat and maybe isn't actually easier to clean! The models that I'm looking at that have Hidden Elements are also the ones with convection, so I guess that makes 2 decisions easier! Thanks so much for all the helpful information.