There's a reason Glock has 80% of the police market sewn up while Kel-Tec does not. Is there any department that does issue them?
There ya go!
Glocks are simple, not a lot of cops are gun people so the easier they are to operate, the better. They're damn near idiot proof. Chamber round, pull trigger, gun most of the time goes off. That isn't cop bashing, it's the truth. To some it's just a tool for work, not a passion or hobby.
Glocks are inexpensive
Glocks can be high cap
And Glock way back in the day damn near gave pistols to police departments. Why spend money on something expensive while 1 company is damn near giving them to you?
Just because a lot of police departments carry Glocks is does NOT make glock the end all be all of pistols. They feel like crap, I've seen them failure to feed, failure to fire, failure to extract, and seen the after of several kabooms. They're a man made item, like everything man made, it CAN and WILL fail eventually.
I've shot a lot of Glocks, and the only ones that felt okay were the $1500+ custom ZEVs. I've never experienced that "Glock accuracy" people rave about. At 3 yards, maybe.
I've never owned a Kel Tec, but the ratio I've had to work on is pretty low compared to Ruger, Taurus, Smith, Glock, Bersa, etc. I've seen a PF9 go 500 rounds in 2 days with maybe only the slide not locking back on the last round, which was due to shooter resting his finger on the slide release.
But, like EVERYTHING man made, they can produce a turd (this includes $2000 pistols and $3000 scopes). Hell I bought my car new in 2014 and it's been in the shop a lot because the "latest and greatest" or the "new improved part" didn't work right.
If they fit your hand, purpose, or price point, I'd say go for it.
That being said, if you want a pocket gun, I'd trust more Taurus TCPs and Ruger LCPs than the P3AT.
I have seen 1 blown up Kel Tec, and that was on a PMR 30 several years ago before they redesigned their barrels (and that was with CCI Maxi Mag ammo)