I have the OTR Advantium 240, I would imagine the wall units work the same way. I know the 240 is more powerful than the 120 but they don't need to be "pre-heated", put the food in and use the speedcook feature and you're good to go! :) I've grilled steaks, pork chops and roasted whole fryer chickens in it, in addition to other things. The whole fryer takes 29 minutes with no preheating, so it's definitely faster than a convection oven. I also have a GE Profile dual fuel range with convection. We never use the range to broil anything since the Advantium is much faster. It doubles as a microwave and we use that feature also. We're considering moving and the kitchen will definitely have an Advantium, I wouldn't want to be without one now.

I have an Advantium 120 over a ZET single oven. As ziggysun said, the advantages of the Advantium are the versatility of the appliance, and for speed, the speedcook feature.

In regular convection bake mode, my Advantium heats up to 350 degreees about 5 minutes faster than my ZET (8 minutes vs. 13 minutes).

Interesting - but makes my decision so difficult. It will probably cost me a grand more than a convection micro, and I can't decide if the 5 minute time savings is worth it...

To building...
The difference (I think) is, that the Advantium works as a REAL oven as well as a convection MW. You can bake cookies in it, whatever. I always thought (and again.. please correct me if I'm wrong) that a convection MW was still just a MW with a fan.

I think there may be a difference between the wall oven and OTR Advantiums. I don't have the "Convection" mode, my options are Speedcook and Microwave. It's been installed since 2005 so maybe it's an older model? I know at the time we purchased, the literature said the 240 cooked 8 times faster than a regular oven and the 120 cooked 4 times faster. I'd be interested to hear if someone has the 240 wall oven and whether it's the same time for heating up as morton5.

The other thing to keep in mind is that the Advantium 120 can toast/broil as well, acting as a toaster oven. This is what really sets it apart from a convection micro.

Can't say I'm in love with mine as much as some-- find the speedcook a bit gimmicky and haven't had great results. Changing out the carousels for micro vs. traditional oven is kind of a pain. Maybe I just need more practice since it is a totally new type of appliance for me. It sure looks nice over the ZET, though, and since I don't have a toaster oven it's nice to have the broil feature.

Can the new 240 Advantium also toast like a toaster oven?

bump, I'd also like to know about the toasting ability of the new 240's.

The ZSC2202NSS (240 wall Advantium) Use & Care Manual (p.21) from the website says it broils and toasts, using the upper lamps, lower heater and convection system. It says there is a dial to select Broil or Toast.

Here is a link that might be useful: ZSC2202NSS Features and Photos - The GE Monogram Collection