The only problem with crossbows is you have to keep replenishing their bolts. When they have bolts they aren't infinite.
Really? let me check...
/goes to other room
/boots up his PS3
/waits for it to load
/checks inventory
/pauses
"DAMNIT!!!!"

Hehe - sorry, I'm a PS3 user, and have only been told certain details about DG when I posted on the forums wondering why on earth my follower refused to use my crafted bow I gave them. I didn't know that caveat about the crossbows.

Incidentally, what about the follower's exclusive Dwarven Centurion Arrows? Surely those can't be limited as they're designed not to be as you can only pick up one...