I switched from a Droid to a Droid X the day it came out, and have been loving it. However, it does have a fair amount of problems that didn't occur with my original droid. Two of these are listed below
1) It randomly resets itself, usually when I receive a call or a text, but sometimes it just happens randomly for no apparent reason. This has happened since I purchased it, and before I rooted it.
2) The Battery Use page in the settings doesn't work properly. This is also a problem I had since I first received the device. I used to love the "battery use" section of my original Droid. But on my droid X, it doesn't work properly. It only shows 2 things in it, and those are Display, Cell Standby, and Phone Idle. the percents also add up to 101% at all times. The amounts rarely change by 1-5%. Other apps that I use don't appear, either. This was a problem since I received it, even before installing ATK.
My Droid X is currently running stock 2.1 Eclair, and is rooted. I've also installed Advance Task Killer. For rooted apps, I have drocap2 and wireless tether for root users.