Dead pixels, twitching screen, ringer stuck in vibrate mode after being set in smart options, camera not working, can't delete text history...these are the major ones I've read about so far.
You can return within 30 days but you have to pay a $35 restockiing each time unless you get a defective phone.. By the way the screen is larger but received texts are kind of small. There is no way to make the text font bigger. Of course you can download other apps such as chompsms. So if you take back the incredible and get the droid x and then go back to the incredible you will have paid $70 in restocking fees.
I have the X and do not have any problems with it. There is only a small percentage that are having problems with their phones you can check out phandroid.com to read in the forums about how many people love the phone. I think you just have to get one and see if it works and if it would have any problems get a replacement