Since you mentioned "summer alpine trips" in your original post, I do not think you will have to deal with the issues of cold temperatures with canister stoves. It really has to be way below freezing for a decent canister stove to start experiencing problems. (and only when it's getting close to empty). On the other hand, if it is really that cold, you can more safely cook inside the tent, where it is hopefully somewhat warmer.
As you can tell, I am a big fan of canister stoves. Whatever you pick, get a decent windscreen. (unless there is a built-in one already). I use either a piece of heavy-duty foil or a piece of fire-proof cloth.

This is kinda expensive, but got really good reviews: http://www.rockexotica.com/ortik/heat_it.html The reason I like Jetboil, is it sort of has a windscreen built in and the system is sturdy enough to cook inside of a tent.

Just one more thing about the MSR Expedition. Years ago when Jean Armbruster (now Myers) and I were climbing on Wallface in the Daks. I was making dinner, white gas sprayed out of the pump when it was pressurized and the stove was lit. The spray hit the stove, the flame burned back into the bottle, and the result was "interesting". The guys next to us though we were a bunch a yahoo rednecks playing with fire.

I don't know why it did that but o-ring in the pump may have dried out since I had used it heavily a week before for a month when I was down in Peru. Maintainance is key to these stoves.