I'm curious, why wouldn't you use your BEST stuff for yout tour? Is this your living, or a hobby? Either way ...... I suggest you use the best available. The laptop I use on stage is a Sony Vaio - best one I EVER had.
I make my living as a musician and as a producer. Taking my laptop on tour is not an option because it is my primary machine for the other half of my professional life. Plus I play in a rock band, I've been on tour with rock bands before and if there's one thing I know it's not to bring along any gear that isn't necessary. All I'd be using are Lounge Lizard, NI's B3, and perhaps a Gigastudio piano, not computationally demanding stuff. If a $100 mini-ATX windows machine can get that job done with the same efficiency as my mac, I'll take that on tour any day over the $1000 liability.