Let me start by saying that if it wasn't for Mike figuring out how to fix the ejector problem (http://easybakegunclub.com/forum/thread/34/Kel-Tec-pf9-FTE---Failure-To-Eject-problems.html), I'd have given this gun a 1. From the factory, the FTE issues were just unreasonable. You can only have a firing pin eject with the bullet so many times before you call it a day.
Instead, Mike came up with the solution and, with the addition of the custom made fiber optic rear sites (still waiting for the project too... we're great on ideas, terrible on follow through), the PF9 is actually fun to fire and at a point that I have no questions about it's reliability. It still jams after about 70-80 rounds but that's just because of how small it is and nowhere for the carbon to go.
My only complaint about the gun other than my issues with all tiny guns is the trigger pull - it's War and Peace long. I won't even start on figuring out why the reset point is almost full length.
I have to add a caveat that I really don't have that much time behind the trigger since Mike's repairs. I do think that Mike should look into that upgraded trigger I posted about.