My experience is mixed. About ten years ago I bought a used P-12. I liked it fine, but it was during a timeframe when I didn't have a lot of money to shoot very much.
The other experience, within the last 18 months, a friend of mine went in on a group buy for specialized hi-cap Paras with custom logos for a particular unit. He couldn't field strip it, he couldn't get the guide rod and plug out. I thought he was just being a dumb rookie, so I went over to look at it, and I couldn't get it out either. We went to a shop and let their guys play with it, and after much prying and tapping with mallets, it came out. They were trying to see wht was wrong, and my friend examines the slide, it was malformed. There was a flat edge inside the slide where the guide rod is captured. We guessed that when they put it in a vise to install the night sights, they squeezed it too hard. We called and explained exactly what was going on, they fixed it quickly with shipping both ways, but my friends was seriously bummed, it was his first handgun purchase.