Howard,
IMHO, I don't think a Macbook will be any better than a Mini. I don't have any personal experience with a Macbook, but I'm currently running a Mini via Toslink to my DAC. Both the Mini and a Macbook are limited to their internal audio cards, and output via USB or Toslink. I've seen posts about a Macbook on battery sounding "quieter", presumably because of reduced electrical noise but I believe the evidence is anecdotal at best.
The best setup, again, IMHO, is a Mac Pro, with a Lynx AES16e card. I'll be purchasing this setup in a week or so and can't wait to hear the improvement.
HTH. . .
Bob