Everyone will have a different opinion. If you like the 92, you will probably like the CP88, as it's shorter and lighter (and generally better, IMHO). And a good used one on here should be £100 or less.

The CP99 is quite nice. The DA trigger is heavy and graunchy, and the sights are far too big. But it's still quite a decent bit of kit and the SA trigger action is as good as the DA is bad. Definitely a step up from the CPS.

Many will disagree, but I have real doubts about the long-term robustness of many blowback BB guns, with some exceptions like the Baikal (not the Umarex) Makarov. And the "realism" doesn't do much for me: it's still a low-powered air pistol, even if its light alloy slide trundles back and forth with each shot.

In any case, I personally can't get enthusiastic about guns that can't group in a maximum of 1.5" (and preferably 1" or less) at 10m, while making proper round holes in a card target. The better pellet firers will do that. I don't know a BB repeater that will.