I picked up one of these along with a buddy. He's run a couple hundred rounds through his, and I've probably put 800 through mine.
I've seen complaints if the front sight popping off. So far, neither of us have had an issue like that.
Regarding ammo, all we've run through them is CCI Mini Mags. We've experienced a couple FTEs and I've, personally, had about 3-4 double feeds, or about 1 every couple hundred rounds. Neither of us have had a FTF.
I have yet to see a 22 semi auto that doesn't have these sorts of problems in some capacity. I certainly don't think the ISSC is far outside the norm.
If you're looking for a 22 with a feel similar to a compact Glock, then I would definitely recommend the ISSC M22.