IMHO it's also pretty damn good for building the machines themselves - just don't skimp on the brackets, and use the deflection calculators to size your profile correctly.
I'd also recommend (again) that you plan your machine and get everythig delivered cut to length - you can then errect accurate megastructures in minutes!
I think I'd also consider buying some of the T-slot cover strips for any part of the machine that's in the way of chips and coolant - you would be amazed how full they get!