I have an SU16-C, on which I've added the "E" (or AR style) collapsing stock. I kept the folding "C" stock, and with the removal of two pins, can exchange stocks rapidly. In fact, with a little bit more work, the folding stock can become a pistol grip, although not necessarily a pretty one.
I love the gun. In fact, so far, I haven't found an AR I'd rather have (not yet an avid AR fan, but I suspect it's coming). The gas piston system is awesome, but even with a polishing job, when racking the bolt, it still sounds and feels as if it isn't as smooth and as loose as I'd like. On the other hand, it's never failed, and I've shot it lots.
Some won't like the plastic receiver rail, but it works, and when considering how much plastic there are in lots of other guns, presents no problem for me.
It uses AR mags, and I have a somewhat concealable set up for the gun. With the stock collapsed, I can put the gun inside a fishing gear bag, along with a hundred rounds in various magazines hidden therein.
I'm an AK fan, and dote upon my Saigas, both shotguns and rifles, but if it came down to it, and having to pack the gun every day, and it shooting to POA and reliably, I would probably pick it as my first line weapon.