Not as talented as Zetterberg, but in some aspects quite similar as a player. Steen is hardly the fastest skater in the SEL and Zetterberg is not very speedy either. They are however IMO good skater because of their balance on their skates. Both can put the puck in the net but are better at setting up plays. One difference is though that Steen has an edge to his game and plays pretty physical (sometimes dirty, agitating his opponents).
Both are very creative and have fine technical skills, but IMO Zetterberg has better potential.