I'm just judging from my current tank which we've been running 2x65 PC
over a 20G on. Yesterday, we picked up a Current 6 T5 fixture (for our in progress 50) and to check it out, put it over the 20. The colors are quite a bit more intense and the light seems to penetrate better with the T5, but since you'll be running halides with the PCs I doubt you'll have any issues with the end result.
Hopefully someone with more direct experience will be along shortly....