Maatta is really good when he's on his game, but I noticed he makes some pretty questionable plays that lead to bad turnovers when he's tired. One game I saw him play against Kitchener, he was easily the best player on the ice. One week later he had multiple turnovers at the blueline in the offensive zone and I was nervous whenever he had the puck. He also needs to work on his skating. For a rookie though he was good overall.
That about sums up Maatta. He's all over the place and kind of sloppy. His positioning kind of reminds me of Jack Johnson at the same age and like JJ I think he'll have a learning curve before becoming a good player.
Matt Finn is a beast in the OHL but I question his foot speed to make it at the next level. His skating is average at best. So while I think Finn is the better OHL player, Matta might be the better NHL prospect.