I carried a Glock 26 for 8 years until I got rid of it and got a compact Walther P99 last year - also hard chromed my slide.
It is a great gun. The trigger will smooth up a bit after 500 rounds or so.
I used a Bianchi 7L holster - a leather belt holster. I think w/ the exception of some of the tight kydex holsters, pretty much any holster made for the fullsize will work for the compact. My Bianchi is made for the fullsize. But, I actually like the little bit of extra leather on the holster. Many holsters do not protect the very end of the gun - the muzzle area. And, when I sit down on a wooden bench or something similiar, I hear the front of the gun loudly hit the surface.
I carried a Glock 26 for many years in a holster made for a Glock 19, so I knew it worked out well, and that is why I did the same for my Walther.
As for sights - I prefer stock sights. But yes, the SW99 sights should fit that gun too.