Hey man, your gun is a personal bit of kit so only realy you can choose.
Heres some of the pros/cons in my opinion:
E-tek
- Better efficency
- Rammer based so more kick than the proto
- easier dissasembly - marginally
- wire eyes
- better trigger
Proto
- Smoother shot
- good stock barrel
- enclosed bolt
- Wire eyes (canbe a bitch)
Both
- light
- great company support
- tried and tested systems
- cocker thread
- shoot HP and LP air
- HPR & LPR
Have ugprades i.e frames etc
I'd go for the e-tek based upon:
Efficency
wire eyes
The higher kick and noise on the e-tek isn't bad and in game one couldn't care less.
I've realy don't like the PM7 trigger and the frame is abit chunky esp once you've tried the UL frame.
Any question just ask as thats abit of a patch review.