I've got three polycoat CZ's, one matte stainless CZ, and one bright stainless CZ. I've also owned a matte nickel compact CZ.
The nickel finish was pretty durable, but I had to be extra careful with it, because it showed scratches and wear more readily than the other finishes. The stainless guns will show scratches and a bit of holster wear over time, while the polycoat guns seem indestructible. I've owned the polycoat guns the longest, but they show the least wear of any kind.
In addition, I've read that there's a cheap Wal-Mart paint that perfectly matches the polycoat finish, for quick repairs (Black DH1602). While I've never used it, it might be worth testing.