I have to disagree, too.
The TM MP7 is pretty decent, all things considered. The "problem" with it is that people approach it thinking it'll be an AEG. But it was never sold or promoted as an AEG. If it's taken for what it's supposed to be, it's a great little gun -- awesome in CQB where you want a compact gun for close range engagements. With some tweaking it's half usable outdoors as well; IMO its a nice secondary for a sniper that wants a reliable SMG for close range.
As for the gas (KSC/KWA) vs electric (TM) bit, they each have pros and cons: the Marui doesn't suffer from gas cooldown or lackluster performance in cooler/cold weather, and dirt cheap mags are available (specially if you get those realcap ones). Downside is limited upgradability (most aren't worth it, despite being available) and pistol-ish power out of the box. The gas version packs a lot more power but is burdened by all the hassles associated with gas guns (notably SMGs), and building up a decent amount of mags to make the gun usable as a primary will easily double what you initially pay for the gun (HK shop prices for mags being in the USD$50 and $60 per unit range, for 20 and 40 round mags respectively, plus shipping and import taxes).
Canadian prices for the gas version being in the 500-600 range, another $500+ for enough mags to make it useful... you can get a really good AEG for that price. IMO the cost factor makes the gas version prohibitive, unless you absolutely have your heart set on a gas SMG regardless of cost.
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