the CZ-75 is the most widely issued pistol in the world. A lot of them seem to be coming up for replacement though, hence the surplus sales.
That's a claim that CZ marketers make, but they never back it up. Most widely ISSUED (i.e., used by more departments) may be true, but the number of guns actually in service is not that great.
The police departments using them were only small ones. South Africa's police used CZs, for sure. But almost NO military units did, until recently. CZ PCRs were used by the Czech National Police, and they later upgraded to a different model CZ. The Turkish military contracted for a large number, took them, and then switched to Tanfoglio-based guns, made under license from Tanfoglio, in turkey. CZ made more, and the overrun was called the Turkish Contract model. I had one -- my first CZ. The PCR (which is an acronym for POLICE CZECH REPUBLIC) is an alloy-based Compact model.
As I said before, none of this is a reason to NOT buy a used CZ. I like them and have had a lot of them. (Still have three CZs [a 75BSA, an 85 Combat, and an 82], and two clones -- and they're all great guns.)
Just be wary of CZ Marketing hype, or parse their statements closely.
As for shooting low -- lowering the front sight would have worked, too, and you could have done that yourself, with a DREMEL. (The front sights on the older models were staked, and hard to replace.)