I'm very biased here as my only gun is a CZ-85b (identical to the 75b just full ambi) and I have a Kadet 2 conversion kit which is a 30 second swap to shoot 22's.
Never shot any 1911's before, but I hear when they are not in 45 or they shorten the barrel from 5' (or whatever the standard size is) they start to get finicky. That being said I'd buy one in 45 given the chance.
Either way I'm sure you can't go wrong. One quick observation the 75b is an all steel gun. Those things are heaaavy. I'm not a monstrous man by any stretch, 6' 240 lbs, but I wouldn't consider lugging one of them around all day.
Just a thought.