Probably it is good to hold, but unlike MP5 or Uzi, this is neither an SMG nor a uSMG. It's a 5.56 carbine that tends to have recoil comparable to assault rifles (much higher than recoil on .45 SMGs like UMP45, 9mm Uzi). The user of this weapon will have to use just one hand (the trigger-hand) for grip because the handle is too small for grip with both hands and the weapon is heaver than a handgun, and position it away from the body (which is difficult if you're used to rifles or even proper SMGs like MP5 or UMP). Like Manc said, this weapon doesn't even have a forearm grip like Steyr TMP that helps your body absorb some of the recoil energy, increasing accuracy. I guess we'll have to wait for feedback from its operators.
I think if this weapon is given a forearm grip, it won't need that awkward butt.