Well, I went through the same dilemma about 2 weeks ago, and went ahead and threw down for the Moment. I won't say I never looked back, because there are definitely things I miss about the Centro. I really don't use my phone to talk on that much, so as far as that part goes, as long as I can place and answer calls, I'm fine. I'm finding that the radio on the Moment is a bit weaker, as I often have little or no signal at work. That was occasionally a problem with the Centro, but not nearly as often. The battery on the Moment really sucks. I think I'm having problems with it at work because of the constant switching between EVDO and 1x as the weak radio searches for a signal. At home, I have been using data a lot to install apps and play around, so I really haven't had a "normal use" day yet to judge the battery away from work. However, I suspect that I'll still not be able to get close to a full day's use without charging. Getting an extra battery or plugging it in when not in use are options. The main other thing I miss is my Slingplayer. I knew that going in, so I chose that problem. However, I'm quite confident that there will be an Android client eventually.
Having said all that, I really like the Moment in general, and Android specifically. There are tons of applications available, many of them free, that make me realize it was definitely time to jump off the PalmOS bandwagon. For instance, the onscreen keyboard of the HTC Hero is far superior to the one on the Moment. So...I downloaded and installed it, and it works much better. It's fun to be out in front of something instead of trying to keep my old technology on life support. I don't think there will ever be one singular IPhone killer, but the explosive growth of Android and the variety of devices available that use it are definitely going to up the ante.