I've had a T-Mobile SDA since October, and
I wrote a review about it here. Three months later, I still love it. But last night I noticed the joystick had some issues... I could move left, right, and up with no problem, and I could press it in, but the down motion on it only worked about 10-20% of the time. That's pretty annoying when the only way to access some menus on the phone is to move down with the joystick.

So I called T-Mobile customer support last night. I spent about 10 minutes on hold before getting a person, which is very rare. Usually I can get through in a minute or two. But that's ok, I finally got someone. We spent about 10 minutes trying various things - soft and hard reset. The hard reset deleted everything on my phone - wallpapers, ringtones, pictures, contacts, calendar, etc. But that's ok because I can just sync it back to my work computer on Monday. I have everything saved on that computer. Plus I have half my pictures saved to the miniSD card. But anyway, all the resets didn't fix the problem.
Theeeen the T-Mobile guy offered to replace the SDA for free. Woo! That was what I had been hoping for the entire time. BUT THAT'S NOT ALL, BITCHES. He also offered me the T-Mobile Dash, the updated version of the SDA, for FREE. (See picture.) The Dash has everything the SDA offers, but also has a QWERTY keyboard and a wider screen. It is also not as thick as the SDA, and a little shorter. (It is obviously a little wider, though.)
Here's the CNET review of the Dash.UPS Express means it'll get here in three business days (including weekends, woo!), so I should get it Tuesday.
T-Mobile ftw!