The MBPs are the best off-the-shelf laptops you can currently buy.
My MBP runs Windows far more than OSX.
Clevo D900 is the mother of all things laptop... but it's $3k well spec'd.
High DPC latency, crap Firewire controllers, limited BIOS parameters, and over zealous power-management have really bogged down most laptops (for use as a DAW).