Do you need ambi controls? The CZ-85 has them, and the 97B doesn't..
Do you have a large hand? The CZ-97B requires itl the 85 is more forgiving.
Want different grips? There is little available for the 97B, yet.
Need a holster? Limited holster options for the 97B, still -- but I think Eric (here on the forum) can fit you.
Have you shot much .45? Are you willing to pay MORE for each shot? Then the 97B is your choice. Very nice gun and very accurate.
All that said, its really a personal decision. Try the grips of both. I had a 97B and liked it, but it was just too big for my hand (and Witness .45s aren't.) I have an 85 Combat. Fine gun.