The Macbook Pro is just good enough for a photographer to get his field work done, but I wouldn't trust it.
I think the big iMac (27 inch) or whatever has a quite good IPS screen and is good enough for photo work when calibrated with current i1 or Spyder.
If you really want good color, then you need to know what you're doing, and probably use a special screen with its own calibrator. I'd suggest Eizo or NEC.
Edmund