In my opinion, commercial wise (clevo), none, as far as the 8xxx godbox. Now the 5660s may have some competition...uhhh...somewhere out there...i guess, but yeah, you need to talk desktops for comparision.
And as far as macs. Well...innovative yes, cool stuff yes...but, not all people run windows on pcs. I know too many people who run linux and some bsd and other *nix variants ON their laptops...im one included. Yeah, i do respect the os, but as far as practical use, many more people use PC based systems. Thats just a fact (reagardless of what they show in the movies ant tv shows, notice they show Macs all the time.) One main reason is most are generally more familiar with the architecture. (hehe..i came here too late, hoping yale wouldnt see that mac post...after, i was like...uh-oh!!!!
The fact that it's a mac is the GOOD thing. You can run to CompUSA, Frys, and several other stores to grab games for them, or you can order online. Windows is an awful OS, and since it's unix based, and has more games avail to it than Linux, it's a better machine. I mean, the whole screen is rendered by OpenGL. You cannot touch it.
PC Dominates the market, and although i have a very deep respect for *nix distros, the games are on the windows platform in the computing world. Period.
Plus, i cant find one Business set up with macs for their core networking systems.
Win2k is "hella" stable, but, seems to be more user friendly than a *nix os. And, truth be told, that is much much more common.