I'll do a quick comparison to the Marui recoil shock series.
Advantages
-Harder kick
-Can use AEG mags
Disadvantages
-Fragile mag/bolt stopper design
-No blowback
-Sewing machine sound of normal AEGs
-Motor sounds like it's in pain(probably a combination of non neo motor+ higher fps spring and recoil weight)
-Hop is not as good as marui
IMHO.they are pretty decent guns,Internals are a bit average honestly,but pretty strong.Not a fan of KWA AEGs to be honest but this one looks good.
Also check out BOLT airsoft recoil series,a more affordable version of both the TM RS and the KWA ERG. The gen 2 versions seem good,but reliability is unknown at the time and the TREMORS style design is a bit worrying,no bolt stop either