Not bad, considering.......
Just do a thorough inspection of it before you commit.
I carry a P-220 every day for duty and I love it.
But, like with anything else, until you really get a chance to go out and shoot it you just won't know:banghead:
Ask him to (or if you can) field strip it at the store (will you get a chance to test fire?), check the barrel, check for spots that are wearing prematurely, check the mag well for damage. Do the mags move around alot? Do they seat well and firm? Is there any sign of beginning rust/tarnish? Keep an eye out for all those things that just don't look right or seem right.......
Personally, IMHO, you are SO CLOSE to the cost of a brand new one (minus all those extra mags), I would just eat the extra and get a shiny new toy. That way YOU will know EXACTLY what has been done to/with this weapon.
I'm not a huge fan of buying used weapons unless it came from a friend or family member, and I have a good sense of the "history" of it. Places like Kittery Trading Post in ME are trustworthy, my local shop I trust too....but beyond that it's just too much and "unknown" for such a serious toy. You mentioned that they are "7 round mags".....are you sure they aren't 8 rounders??? Is this a Cali. limitation??