If you do get a Macbook Pro I wouldn’t get the new Retina one because it is pretty much upgradeable.
For those who are in UK there some nice deals going on now for lenovo laptops:
http://www.saveonlaptops.co.uk/lenovo-cashback
If you are running a pc and running into CPU spike issues, set your shortcut to load traktor via command prompt and set the affinity to cpu 1 instead of zero.