I have an older model of the C9, the compensated model, that has over 2500 rounds through it. I did just replace the firing pin and spring assembly for a newer design that is supposed to deal with some light primer strikes that some report having, I have had a few but only with WWB target ammo. I replaced the ejector key and spring as well, I wasn't having any problems with it but the gal at Hi Point said she would send them to me as they had added a coil to the spring and redesigned the ejector key as well. Well... I'm not ever going to complain about free parts! Three days, had them in hand. The guns are easy to work on, and teardown isnt that difficult, there is a roll pin that you have to drive out that goes through the retainer, other than that little quirk its simple.
Fixed barrel with the blowback design, very accurate shooters. I have the C9 Comp and picked up the .40 JCP about six months ago, have about 300 rounds of mixed Federal Champion, Blazer Brass and WWB through it at the range, and fired 50 Magtech Guardian Golds through it without a hiccup.
What problems people seem to have with them are usually with the mags... quality control on them seems to be lacking, as the spacing on the ears vary widely and will cause a double-feed if too wide or jam the nose of the round into the feed ramp if too narrow. I had a mag that worked perfectly, so set all the specs to the same and they worked great.
Not a good choice for a carry weapon, even if they are proven reliable, as I don't like that the striker is at full tension with a round chambered. Failure of the sear would cause a discharge, and even with the drop safety I dont like only having one mechanical link that is preventing disharge. No cases that I could find of this happening, but worn parts could lead to it down the road if people don't inspect them periodically.
Bang for the buck, you can't beat them. If you want a car or truck gun, then by all means. If someone breaks into your vehicle and steals an "under $200.00" pistol, that isnt a lot of tears to be shed, not like it was a Kimber or some other $1000.00 gun.
Lifetime warranty whether you are the first owner or the fifth, usually a week turnaround till you have it back, and a free magazine for your trouble... what's not to like? Sure they are heavy, the .40 weighs in at 37 ounces and feels like you could knock someone out with it... heck, I KNOW you could! Its nice having something that I can just go out and shoot the heck out of things with for so little cash out of my pocket.