I had a Kriss Vector which I just had to sell to fund some auto repairs. Thing was awesome. Accurate, zero muzzle flip, etc.
Cleaning it didn't take long, but it does tend to hang on to every little bit of grunge. Super easy to take apart.
Preban mags aplenty - glock mags. I realize they are more available than probably any other preban pistol mag, and that I'm almost certainly the only person who will ever say this, but I didn't like dealing with the glock mags. The Kriss didn't love the U notch ones. The wacky pricing all over the place, the uncertainty of getting ripped off for non-preban square notch mags. All my guns are metal, so maybe that's it too - I just didn't like the plastic mags. You also needed to file the top of the base plate down a bit to get them to seat reliably. I dunno, I just found it to be a real pain in the ass...I know I'm weird and that no one would ever agree with me on that, so probably not a huge concern.
If I was a glock guy and had tons of mags hanging around or if I lived in a free state I would DEFINITELY consider picking one up again. You definitely need a 30 round happy stick if you own one. 10 round mags are just not an option with it...you can go through that in a second. Zero fun factor.