I was fortunate enough to get a KSC MP7 this past weekend. Internally it's just like a GBB...but it's meant more as a SMG/PDW, so I figured I'd throw it in this thread eventhough it's not an M4, SCAR, AK or "traditional"

GBBR.
I've always liked this particular PDW as a concept and it's seems like the real one is nicely built. However, I was really dismayed when I bought/handled/used the airsoft version. Under-impressed was a massive understatement. Weak FPS, "delicate" and one of the wussiest AEG sounds ever.
When a local got the KSC MP7, I got a chance to fondle that build for a bit. It's solid. Even without a mag it feels like a solid piece of machinery. The main grip has always been a bit of an odd fit for my hand (the rounded palm portion doesn't fit my mit nicely)...but it has that feel of picking up a well made quality tool.
Build quality is excellent and the fit/finish of the internals (i.e. slots/rails, reinforced areas, metal to metal contacts, levers, bits & pieces) is excellent. The charging handle (polymer) seems a little weak. I've racked and smacked it pretty good and it's held up...so I suppose it's better that it's flexible vs. brittle.
A local guy has blown his nozzle (same as with a GBB on propane) already at a toasty warm indoor game. I'm searching for replacement nozzles already to get a couple just in case.
*small note* - the orange paint that was on my tip came off almost as soon as I sprayed some paint stripper on it...it just sloughed off leaving the black finish underneath. Near immediate...which was nice!
I ran about 4 mags through it on duster. What a racket. This thing is LOUD. On a fill of duster each mag is good for about 2 full mag fills (30rnds loaded).
I just field stripped it, not a full disassembly. It's a dream to work on though.
Don't know about it's accuracy...For tactical CQB trials engaging Tangos "Across the basement", it's more than adequate. The "pistol" sights ride really low...the "rifle" flip-ups are much easier to use. The retractable stock is pretty sturdy with little wiggle (feels tight like a new CA MP5 sliding stock). We'll see how it holds up.
I bought this one for the upcoming winter season of indoor CQB stuff. With a couple of mags and a backup secondary...it's a nice setup.
Tys