Look up classic airsoft, they were the original airsoft. So with a P*, you're just wannabe old school
I'm not that versed in Mechbox setups, I can crack one open and do the very minimal if I'm really lucky/got lots of time to kill. Even then I usually let somebody who appreciates the workings fondle it.
I've got mad love for my P*, I would throw one in almost all my guns if I could.
Want high ROF? Simple push of a button, few flips of that button and bam.
Less/More FPS? Pretty damn simple.
Get used to the hose pretty damn quick, hasn't slowed me down.
It's shit simple and reliable. At most, you could break a nozzle as long as you work within the limited PSI range.
~$20 later, and you have a new nozzle, 5 minutes of time and the nozzle is installed.