T-mobile? Gawd, I hope not!
They are pathological about hobbling everything!

The HipTop/SideKick started out a nice device with a strong developer network... they locked it down so you had to be a published developer to get a key to install software that they didn't have in their "store"... which absolutely blows. There were a ton of apps on the (former) SideKick Developer Network site that I wanted, and I didn't care if they were "beta" or not. In case it doesn't stand out... if you can't test the app on your device, you can't release it, so when they changed the rules for becoming a developer, they essentially shut any new devs out.

Now look at what they did with the G1... which I would absolutely love to have, but they're locking down a device that you're not supposed to be able to lock down.
I was thinking about paying full retail for one and switching to AT&T, but I've read that they even hobbled the radio so you can't use the G1 on AT&T's frequencies! (I sincerely hope what I read was bull)
In case you're wondering... I like the G1's keyboard. None of the other Androids have anything close. Heck, I'd rank that keyboard way above the one on the N900 (though I think I'd prefer the Nokia if the price were more realistic).

I'm afraid of what they'll do to this thing when they get their greedy mits on it.

Disclosure: I've owned the SideKick (1) Color and SideKick 2 for about 6 years, and if it weren't for T-Mobile, I would probably have bought the SK3 when it came out.
They really do have a F*(# the customer attitude.

(if you want specifics, I can write a book)