My friend has a mac mini, i've used it on several occasions. Its not really the GREATEST of macs, thats for sure. I've only used i think garageband on that though, started to lag heavily with several tracks and effects.
I've heard iBooks aren't the greatest for recording as they can't handle alot, but is probably the equivalent as the Mac Mini.
Personally, if you can't afford the higher end Macs, i wouldn't recommend it in a recording environment, because i was thinking the same thing but i was told theres no point getting a mac unless its one of the more expensive models whereas you can get a perfectly fine PC for the same price as those low-end macs.
Im still a fan of macs, and my next computer/laptop will be one, but don't get one unless your willing to fork out the bigger bucks...IMHO.