I do not have the p9 compact, but I own a p9 ultra.
My p9 does not really like sharp nosed bullets, but beyond that it is 100% reliable. I have over 3000 rnds (at least, but I did not check my records) through mine and the only problem I had was a broken slide-lock. Appearently there was a soft lot of them and mine was one of them. My ultra is pretty accurate, soft recoiling and has an excellent trigger. The trigger itself is what sold me on the gun. It is very smooth in both da/sa and in sa it releases with no overtravel.
If I come across another p9 ultra in 40s&w, I will buy it on the spot just to have a spare.
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P229 Sport and 357 SIG, H&K P7PSP and 9MM, Dual Perfection!!