Ntec isnt an all round weapon, while star 556 is. I leased the far once and i felt that its a slightly improved version of star 556 but with a smaller clip.
One of the areas which ntec lacks is close combat. Lets not talk abt a duel vs smgs. Put a ntec vs star in close range combat, the star556 user can jump strafe or circle strafe while firing without losing much accuracy. You dont have to go to marksman mode cuz you feel like playing with a carbine. Its not easy to do the same with a ntec. The only thing you can do is lean jump and fire. Hell yeah ntec requires more skill than star 556.