I have the alloy-frame P12, but I can't compare it to the G30 since I've never fired or handled a G30.
My P12 shoots more accurately than I can aim and is absolutely reliable with ball and hollowpoint ammo, though it doesn't digest SWC bullet styles well at all.
I bought mine NIB, and made two mods to the gun (by competent gunsmith):
Since the P12 uses a stamping similar the Colt Oficers Model to cap the recoil spring, it is similarly subject to fail after some thousands of rounds due to crystalization of the stamping. This failure would send the recoil spring downrange. I replaced the recoil spring/guide rod/cap assembly with a kit offered by Ed Brown.
Mine had a trigger pull close to 7 pounds, which has been reduced to about 4 pounds.
I think $360 for a P12 in reasonable condition is a great opportunity, and I'd certainly get the gun. Since you already have a G30, you'll have no problem with the 'fat grip' of this staggered-mag gun.
Good shootin'.