Since I am a fan of both players let me give it a shot.
Niku
Maurice is not a big fan of Sami's yet. It kind of starts and ends with that. This was suppose to be "the season" with the gaping holes in our roster but everything went wrong. Sami started out injured and was rarely healthy and when he was he played a bit erratic.
Niku is really good at some things but they are mostly offensive in nature or in transition. His weakness is that he is still not good enough defensively or without the puck for Paul's liking. I think he can eventually get there but I also think he is running out of chances. I think next season is make it or break it time for Niku and I hope he will make it. I would love to see him play bottom pairing with Poolman sheltered next season. I think they could both do well in that role.
Samberg.
He is 6'4" and 215 so he is really big and Maurice loves his Big D men
"FULL STOP" (I could quit right here and it would be enough)
Dylan strengths are the opposite of Sami's. He is a modern day shut down defender, mobile and aggressive he attacks the puck and forces play without the puck. He is the ideal complimentary piece to a guy like Pionk because he plays a safe, clean, rugged game with plenty of skill.
Its the kind of young player Maurice can trust more because his strengths are coach friendly.
It may take him a bit to get use to the speed of the pro game but he plays a pretty low risk brand of hockey and I think he will be fine by as early as Christmas.
Summary Apples (Samberg's size and style) vs Oranges (Niku's size and style)...................Maurice is addicted to apples and he even eats rotten ones and Paul has an allergy to citrus.