I've had my 5th Dinc for about 2 weeks now, and the battery cover seems to be loose from the multiple daily battery pulls. Its loose and makes a creaking sound.
phone #2,3 and 4 were refurbs, number 5 was a brand new one. #5 needs a battery pull about once a day, sometimes when it randomly reboots, it gets stuck in a boot loop and the only way to stop it is to pull the battery. If they'd let me switch to a different phone i would, but they wont. I am hoping that froyo has the much needed fixes for this phone.
If it's any consolation, I did have the random reboot problem on the Moto Droid I used to have. The problem disappeared after Moto's first software update. Your boot loop problem seems a bit more serious though, and I doubt the 2.2 update will fix it. Good luck!