I just had my 2nd barrel put into my p9 ultra 40. Excellent gun and very accurate (after a good custom barrel). I have now shot mine for nearly 10 years (I did not check the records for the exact date) and have found it to be very reliable and fun.
I have had no parts breakages, very few failures to feed and fire in over 5000 rnds. I say very few because I am sure they happened, but I do not remember them.
If I found another P9 ultra in 40, I would buy it just to have a spare.