Man, this is a tuff one. I own both, a West German P-226, and a CZ-SP-01. All I have to say is, just having such outstanding pistols to choose from makes me proud to be in the USA. I feel we are truly living in an age were we have some of the best guns ever made to select from.
You can't go wrong with either, so there is no "best" choice. I think it has been suggested to try them out if possible.
If mainly for range work, the extra weight of the CZ is a plus, making 300 round sessions a joy, wishing you had more ammo. The drawback to the CZ (and the Sig) is if you miss a target, or shoot some wild groups, it's your fault
The Sig has a higher bore axis, is lighter in weight, and would better double as a carry and range gun. The Sig is as reliable as any auto-loader made, maybe having a slight edge over the CZ, but very, very, slight (if in fact it exists).
Me, I always pick up my CZ when heading to the range.