This MK5A5 is a solid gun with a good bit of weight behind it. The one I received chrono'd at 410 fps as expected of a Chinese clone gun. Overall it is a great gun but it has a few little problems which might be dealbreakers for some; the retractable stock has a little bit of wobble behind it (but that is to be expected), the magazine has a little bit of wobble (remedied by electrical tape on the mag or magwell), and the rear sight comes loose on occasion (though it can be removed and tightened easily). I'm unsure of whether this applies to this gun that others have received, but the magazine release on mine is quite stiff and sometimes gets stuck in place after I remove a magazine.
This gun can hold 8.4v or 9.6v mini batteries, though both are quite challenging to fit into the front handguard; I believe every MK5 with a front hand guard holding a battery is like this though. The battery it came with is a 1200 mAh nunchuck which takes the same amount of effort to fit in the handguard as do the typically shaped batteries.
Full metal upper receiver
Sturdy ABS plastic Handguard and Lower receiver
Full metal gearbox
Shoots at a high fps
Very accurate with .25 bbs outdoors; drops off after 80 feet with the hop-up all the way down
Stock wobble (though this is present on the real steel)
Stiff magazine release
Lower rate of fire (not particularly a problem for me)
These are easily remedied:
Noticeable magazine wobble
Thick, cheap grease in the gearbox; not particularly harmful but maintenance with higher quality grease or even silicon oil can be helpful
Rear sight comes loose after extensive adjustment; it can be tightened by being removed and tightening the screw underneath
Rating: [5 of 5 Stars!]