I got this from iPadForums.net (a whole site dedicated to iPad use, and which has one forum for musicians using iPads):
"The iPad has three advantages over a Mac: portability, the touch user interface (not to be underestimated), and price. Though there is some overlap on the last. In all other areas (computer power, available peripherals, and powerful apps) a Mac is the more capable device for just about everything, including music creation.
So the real question is if the iPad will be enough for what you want, or if you need/want and can afford a more powerful solution.
Both amateurs and professionals have created some amazing things using nothing but iPhones and/or iPads, but I don't think any of them would argue that a more powerful setup couldn't have done more and better."
So, is an iPad as powerful as a Mac? No way. But are people using iPads to make good music? You best your ass. Is an iPad a legitimate tool for making recorded music? What a stupid question - of course it is. Should you laugh at the use of them to make music? Depends on how much you like jeering at things. Would this site be served by having a forum dedicated to tablet recording? Well, it would attract people who use tablets to record, because tablet recording has its own issues and challenges and experts, so I'd say yes. Will I be bothered if this site doesn't attract people who use the new touchscreen technology? Not much. If I get a tablet for recording, I'll just go to a place like iPadforums.net to get my questions answered, which is what I'm already doing anyway for certain things. I go to Adobe to get my Audition questions answered - I don't go to the Audition forum here. But on that last note, if I compare the utility of the Audition forum to the utility of a forum dedicated to tablet recording, I'd have to say that the latter would win hands down.