I've had a couple of the K2P's and love them. I have a B6P compact as well. Also have just picked up a K2 45 and it's a steel framed piece, excellent as well.
To get back on topic, the K2P is great in that it's a smooth shooter, great tolerances and nice high grip placement allows excellent control.
The difference between B6P and K2P is not tremendous - but as a user you may care like I do (being left handed).
- The K2P has ambi safety where B6P doesn't.
- The K2P also has a built in rail, and B6P doesn't.
- The K2P has serrations on the slide at both front and back of slide. While I only use the back ones, I've yet to find a downside to more grip on a slide, especially when the design is slightly lower profile from slide being inside the frame vs outside.
All this said, both K2P and B6P are nice shooters that feel really great in the hand. Currently I've seen K2P through a couple retail blow out sites under $300, though I've also seen distributors raise cost on them almost $50 in the past 6 months, so anywhere around $300 is a good deal it seems.
Trigger feels nice, gun is reliable and you can use Outbags holster for CZ75b or find a similar Sig model that will accommodate.
Extra mags - either buy factory EAA mags for CZ75B or you can buy the MecGar 17rd mags that work well, aside from a couple I had which were a smidge tight when pressed all the way in - didn't click affirmatively. I read somewhere that a small filing of the top of latch hole on mag worked well, tried it and yep, just that little relief was all it took.
As far as Witness mags, they're almost exactly the same, but NOT CLOSE ENOUGH. They're too thick by maybe a 1/16th of an inch and while you can stressfully press one in the handle, I hope you lubed it to get it back out
Too tight and don't drop free like the CZ75B or MecGar mags do. They're consstently available at about $25 ea if you search for them.
Also to note, Sarsmilaz is the only licensed clone of CZ - so they're doing a nice job making their pieces instead of being a second rate copycat. That and the fact that they're the 2nd largest producer of sidearms for NATO tells you they're not novices at this. Glad to have these coming more available.