they didnt send you a whole new phone? i doubt its a refurb since the phone just came out. but i would have thought they would have just sent you another whole phone.
when i called to get my replacement i got another new droid x. like the whole 9.
Replacements are rarely a whole unit... It's a refurb or one set aside for replacements, and should work fine.
I had to replace my X due to the keys at the bottom not responding properly. Called in on Tuesday, phone arrived this a.m. Just the shell. I keep my battery, card etc and send the shell back.
Rock on!