Does your band mic all the amps into the PA system?  If not, I doubt the 75 would be loud enough for you, and the 30 definitely will not be.  If you use a POD, you still need an amp, right?  If you're always using the PA system for volume, what about during rehearsals, or playing at home?  An amp gives you some flexibility this way that the POD does not.

Are you equally happy with the tones from either choice?