I like Glocks, but find the 21 to be too big in the grip to be comfortable. (I've had a 17, have a 34, and will someday get a 35.) The .45s feel like 2"x4"s to me.
The big Glocks are okay with regard to accuracy, but I've never heard anyone claiming they're exceptional.
The 97B, on the other hand, may be CZ's most accurate pistol.
I had a 97B and found the grip a little bigger than I liked. Try the grip on one -- if you find it OK, you'll probably love the 97B. (Since "big" wasn't mentioned in your reference to the Glock 21, I suspect it'll be okay.)
The 97B and the SIG 220 are considered the best out-of-the-box DA/SA .45s available for under $1000.