I have one, and also had a 75bd for years.
Believe it or not the two are nearly identical in size...height, width and length. One difference is the LOP distance due to the longer 45 cartridge. This gives the perception of being wider, but it's not.
The full dust cover also makes it seem bigger. It is somewhat heavier than the 75bd.
Now one thing you'll have to get used to is the barrel angle . Both the CZ and Witness have sights that are not in line with the slide, as the barrel is actually lower in the front than the chamber end. I still can't get a straight answer why it's designed that way.
I used mine in matches to good effect. Really it's up to you whether you want the option of 'cocked and locked' or not. Don't forget to get a 15# hammer spring right away!
Also grip choices are limited. The wonderfully famous 'coke bottle' grip shape is lacking on the 97, but I was fortunate to find Nill grips at Numrich for $50 that restore the ergo's we all know and love.