My sig is great. Mini-mag NEVER has had a hang-up and Federal bulk ammo works great for the first 200 rounds or so before it starts to gunk up the workings because it's so dirty. You'll get the odd stovepipe here and there afterwards until the gun is cleaned. Nothing else I've experimented with works that well (winchester super-x, other cci stuff). Don't buy a used one, buy a new one (some of the older serial number used ones were reported as having a lot more problems, which is why there are so many bad reviews on line).
That said, I can't argue with anyone who suggests you look into a CZ Kadet instead.