Cold Steel has a far tougher lock and is far cheaper even with CTS XHP.
Zero Tolerance is more fancy materials, fine craftsmanship and pride of ownership.
Also, these days it seems like ZT is getting away from their "hard use tactical folders" and concentrating a lot on the high-end fancy collector runs. Witness the discontinued 0200, 0300, 0550, 0560, etc... in the past few years it seems like the ZT division has somewhat shifted its focus.
If I had to bet on a knife winning some kind of strength or toughness contest it would be the Cold Steels. And not just that but also Axis locks, ball locks, etc.
Sorry, but framelocks simply aren't very strong. IIRC they're not much (if any) better than a well-made liner lock. "My ZT lock failed" is usually met by "there's no reason to spine whack a knife" or "you must have been abusing it". Yet for some reason ZT does not make a slip joint.
I think this does irritate some folks.