Thanks all for the responses, and tho I appreciate the car analogies, the reason I am willing to defer is not that I don't have an opinion, but we're talking about ccw and self defense. He has a lot of experience and training, and I do not, tho I've carried my G19 for 5 years and trust it. I like how the PX4 shoots on a flat target. But, I've never had to defend my life or been in a gun battle, thank God.
I like the Langdon Tactical review... that supports my initial conclusions. So no one else in the self defense world agrees with my friend that it is not a gun to trust your life with?
For every loud person on the internet, or "professional" with a positive opinion about a gun, you will find a negative opinion about the same gun if you look long enough.
The bottom line is if the gun shoots alright for you, and YOU are comfortable with it, it doesn't matter one bit what your friend, or any of us think. This is a question we really can't answer.
The one and only complaint I've ever heard about the PX4 guns is that they are a little chunky for comfortable carry, but that is dictated completely by your physical dimensions, and style of dress.
If you are concerned about the reliability of the gun, then you simply have to shoot it more frequently to ensure it is reliable. Changing guns because one or two folks tell you they have heard about issues is really putting the cart before the horse.
If you want to try other options to see if a different gun works better for YOU, then renting guns can help with that. I have a rotating attitude on many of my guns. I designate dollars for a gun, and if I decide it isn't for me, I trade or sell it to fund the next experiment. It's a matter of what level of experimentation your wallet can tolerate. If the answer is zero, then shoot your PX4 more, replace recoil and magazine springs as needs, and carry on man.
And don't put too much stock in what "respected individuals" in the defense world think. There reviews are always tainted by personal preference. They can't answer those questions for you.
A reverse example: I can't stand Larry Vickers or anything he writes. He is an advocate of the HK45 as it's development involved his input. But if I'd based my purchase on my dislike for the man, I never would have bought an HK45. I put his opinion aside, and bought one, and it is one of the best guns I've ever owned.
Reading reviews and input from friends is fine, but you have to make your own decision here.