I haven't shot or handled a P1 yet, but I do have a TT-33.
I would go for the TT-33, not because I own one. But because ammo is still relatively cheap and you can stock up on ammo. Just for a shooter, the TT-33 is excellent (just as long as you know the limitations of the gun - it is not and will not be a target piece). Plus, I like the recoil of the round and the noise it makes - all for a cheap price too.
In my experienc, it is more than adaquate in dispatching the invading hoard of pop cans and tin cans.