I wound up buying the G2 and I have to say I love the phone itself but I'm a noob to smart phones and haven't even scratched the surface of them.
The one negative I would say would be the horrendous battery life. I don't know if it's just how most smart phones are(seems to somewhat be the case), or that the battery isn't broken in(don't even know if this is a legitimate or even possible excuse), or just that this specific phone has bad battery life, but with heavy use, you're not making it more then 10 hours max without a charge before it basically dies.
I don't have much experience with the Droid 2. I played with it briefly and it seemed quite nice as well though.
As for T Mobile, I will explain it as follows in my short experience(less then a week). I got the phone home and even in the store and had full HSPA+ speeds and I must say this phone just flew, like WiFi type speed. Then I went to a friend's house about 10 miles away and was getting only one bar and it was lagging close to dial up speed, even timing out here and there. T Mobile's coverage can be outstanding, but it seems spotty. With the negatives I've listed, combined with some BS going on with the retailer I bought it from, I'm really considering returning it and going with AT&T and an Iphone, or Sprint with the Evo, maybe Verizon with the Droid 2 Global.
That said, again, the phone itself is really just awesome minus the battery life, again, see above though.
On a last note, I really thought a slide out keyboard was a must for me. I always liked that style of phone better, but even though I still find myself using it just because I honestly do enjoy a physical keyboard, within a day of having the phone I was a wiz on Swype and now find myself using the touch screen probably 75% of the time if not more opposed to the slide out and the G2 really does have a pretty pleasing physical board.
Hope this helps a little.