I bought a Sentry model 7311 at Walmart (appears identical to the 4311 at 4 Seasons) when it was reduced to $349. While I think I got a good deal, it's probably the absolute minimum you'd want in a safe. It's not too heavy for two kids to toss into a truck or van, which is good when you're bringing it home, but not so much if it's being slipped out your back door.
The door looks massive and impervious with all those shiny bolts, but the sides are only .080 thick (a little over 1/16") including paint. Maybe 5 minutes with a Sawzall would peel a side right off. Less time if the safe is located near your tools.
And while I'm at it, since this is Mass. and my guns are of course always locked up and inaccessible, I wouldn't appreciate the keypad loudly beeping at me while I'm sneaking into the safe for a weapon with burglars in the other room. I think I'll disable that.