Hi, Shane!
I'm going to disagree with dtreo. Since you're an iPhone owner, you're a GSM customer. And AT&T's Tilt2 (their version of the TP2) is excellent. Great screen, carrier bloatware was minimized & mostly useful, And data speeds are certainly going to be tons better than what you get now. One of the advantages of the Tilt2 is that it comes with WM 6.5, so there are no hiccups in upgrading from 6.1. And WM 6.5 is very stable. Does your carrier's TP2 come with WM 6.1 or 6.5?
I'm not sure about how the iPhone handles installations or uninstallations. WM (like regular Windows) uses a registry file to retain some settings. When something is installed that requires using that to retain certain settings, it usually requires rebooting the phone to get the OS to recognize the change in settings. I tend to try a lot of things, so I've had a lot of "soft resets" (reboots). And, in the 9 months I've had the phone, I've had only one "hard reset" (return to original factory state, requiring installing everything, again). That was from experimenting with something that was friendlier at installing than it was from uninstalling. That was unusual.
As for being discontinued soon, right now I don't expect it to be. It's a great phone. When WP7 comes out, that might encourage carriers to drop previous WM phones, but I'm not sure WP7 is going to have the initial impact that MS would like. I'm not sure about UK carriers, but US carriers will let you return a phone within 30 days, no charge. So, if your carrier does that, try your carrier's version of the TP2 & see if you like it. If you don't, return it & try something else. If you do, then it doesn't matter if it's discontinued -- you'll have a phone you like with the apps you need before that becomes an issue. My feeling is that, if you have a phone that does what you want & in the way you want it to, then you're golden. Especially if it will do that for a few years. I don't need the "latest & greatest", I need what will do what I need in the way I want it to work, for a period of time. My phone is a tool, not a fashion accessory. So, I'll spend extra on apps & UIs to make my phone work the way I do. When it does that, it'd be pretty dumb to go running off to something else that would only require me spending more money to get back to that result.