The MotoBlur Facebook account synced with all of my contacts...except one. Not sure why it missed just one. MotoBlur synced him from my Google contacts, but FB won't pull him into the phone. Tried removing and adding the account 2x now, still nothing.
But to answer your question, yes it does sync with your contacts. For the most part.
Edited to add: Amazing. in my quest to fix that one contact, my MotoBlur account is now NOT updating my FB contacts. Great.
A few hours later...fixed. Had to uninstall the FB app and removed my FB account from MotoBlur for about 2 hours. Turned off the phone, removed the battery, then added my FB acct to MB and then installed the FB app. Was browsing FB for about 30 mins then checked my contacts, and they were there. My one friend is still not there, but I'll take it.