The simplicity and reliabilty is great with the 2.2/2.4L. They are pretty fun to drive. Good power. I average ~30mpg per tank with my Cobalt w/ mixed driving, so you can probably meet that with a 3.5 or 3.9L. My only gripe with my 2007 2.2L is, on ANY start up with a more than a few minutes down time, the engine sounds like it's coming un-glued on startup. A dry start type noise. It's done this on OEM and A/M filters, 5w30 and 5w20 oil, dealer can't hear it. I just ignore it now.
Joel