The weight difference is very slight, we're talking two tenths of a pound. Even with the alloy frame I've had people say the P-01 is heavy. I guess I can see their point too, the P-01 unloaded weighs the same as a loaded Glock 19, not exactly the same but very very close.
I agree with Tekarra, the rubber grips are very comfortable on the P-01. It would be nice if we had more wood choices than Cocobolo though.
Personally, I find the weight difference between the two to be negligible and I've handled both. The local gunshop had a killer deal on a used 75B that I wish I had jumped on. It was loaded, competition fiber optic sights, Cocobolo grips, trigger job by CZ customs and a custom hammer. $439
I'd buy whichever one you can find the best deal on. They're both great shooters.