I'll do a review of the Magpul body since I've been trying to gather info on it. *Note: I don't own one, this is based on info I have gathered.
Brand: Magpul MIAD PTS Metal body
Manufacture type: die cast aluminum
Insignia / logo / selector finish: logo is engraved, selector marks are engraved and painted. Unique serial numbers.
Finishes available: black, dark earth
Insignias available: Magpul
Included with body: receiver pins, ejection port cover, forward assist knob
Working furniture?: No, when you pull the cocking handle, the port cover will open. The inner dust cover (fake bolt) will not work, it's too tight of a fit and may need modification to work.
Metal hop up included?: NO
Fitment with gearbox: Fits Marui version 2 gearbox tightly, does NOT work with CA gearboxes
Fitment with other parts on assembly: good, some front ends may not fit all the way tight to the front of the body due to the threads being slightly longer
Magazine fitment: good
Notes on assembly / issues with metal body:
The fake metal slide may bind with the hop up. Note that the experimental kit has a removable trigger guard, the Magpul receiver sold on it's one has the trigger guard cast as one piece with the lower body.
Overall rating: 7.5/10