Personally I'd steer clear of the MAC 10/9 and the RPB and PS .380 MACs. Mags can be very hard to find and expensive when you do (look for Walther MPL/MPK mags). The PS MAC 10/45 and the SWD M11-9, SWD M11A1 are by far the easiest to get mags for.
I also wouldn't worry too much about durability. I've got three SWD M11-9's and have owned an SWD M11A1 - they will hold up just fine to tens of thousands of rounds. The only parts you really need to worry about are the cocking knob, sear spring, safety assembly (made of very cheap pot metal - I just threw mine out), and the front takedown pin IF its the type with a ball detent (if its the two piece front pin, you should have little to worry about).
The SWD M11 is nice in that it is by far one of the most versatile MACs out there and has tons of accessories and modifications you can do to it. The PS MAC 10/45 is a classic though. You simply can't go wrong with one.