The wife and I just went out last night and picked up two new 8gig 3GS's. Not bad for $100 a piece with new service. I'm pretty confident in our purchase even though we're with AT&T now. The AT&T network around here at least is pretty good, maybe a hiccup every now and then. For the most part, we will be on wifi when doing anything online. We both got the 200mb a month plan for that reason. Why pay more for something when you already have another way to get it that's often free and faster than 3G. A lot of people got irked by the new data plans that AT&T released, but it's starting to calm down now as many people realize they really aren't using that much data, and the ones that do are starting to connect more to wifi.
As far as the iPhone4's go, we just didn't want to wait 3-4 weeks to get them in, plus we just didn't see enough of a difference to warrant spending $100 more per phone. The retina display is nice, and I'm sure it's great with smaller text and whatnot, but with the 3GS and 4 side-by-side, I just didn't really see enough of a difference. The extra camera and flash, meh. I didn't let the antenna issues with the 4 really influence the decision to go with the 3GS, mostly because I will always use a case anyways.
I briefly thought about getting an Android phone of some sort, but in my line of work (IT and photography), the iphone is pretty much an industry standard and there is a lot more support. The app selection is just incredible, I really do not think anyone will ever catch up with them, although I do like the open source architecture of the android platform. The big thing is while yes, apple and Steve Jobs do have things locked down pretty tight and they're starting to act a little arrogant, they're damn good at what they do...they wouldn't have come this far if they weren't.