The metal on the slide is softer. If it cracks though, I think all you have to do is send in the pistol and they will replace the slide. I have heard of people on rimfire central putting 20K+ rounds through the weapon with no problems.The best thing I can say is, they work 'til they don't.
They're not built to last, the metal used is soft and cracks easily.
If you plan to shoot it a lot, look elsewhere.
It's principal claim to fame is the ability to suppress them easily and they are an inexpensive way to get into a "quiet" toy.
For the same money, I'd try and find a Buckmark Micro (4") model and be well ahead.
Mine started having problems after 5000 rounds. I had the gunsmith at my shooting club replace both the recoil spring and firing pin spring and it's back up and running.My P22 was great for a little while, but now it fails to feed and/or eject on almost every round! I have completely pulled that thing apart and cleaned the living s**t out of it, but it still won't function correctly.