Hi, I have an intel core2 duo iMac, 4gb memory, 250gb HD. I have a 30 gb partition on it that runs windows XP. I use Bootcamp as my "switcher." I have both versions of BIAB 2010 on each partition. I also us 2 1tb external firewire drives for all my loops, RT's,sound files etc. 1 of course is dedicated to mac, the other XP. Yes, the windows version does have a few more features than the mac version. The difference is that the windows infrequently, I repeat infrequently likes to hang. I have never had a hang-up on the mac side. I use Real Band, and Powertracks on the XP side. Again, a few hang-ups. Had to reset external folders for RTs and Real Drums etc.
On the Mac side, I use Garage Band, Logic Pro, and Cubase 5. With the ability to be able to integrate BIAB with my DAW's, no hang ups. I am in hog heaven. Both are dedicated DAW work stations.

Why do I have both? More XP users to go to for help when I get stuck. Also, I usually can transfer the info to the mac side. My next computer this fall will be a 27" iMac. 1tb hard drive partitioned with a 250gb for XP, the rest for mac.

In conclusion, BIAB windows..More features, but not that many more. BIAB mac.. fewer features, but not that many less, rock solid. If finances are a consideration, XP. If dual platforms are of use, especially with pro apps like Cubase,Logic mac. Either way, with BIAB you will enjoy making music.

Hope this helps.
TakeCare
Bill
ps. Mac will run windows 7.