I love Ryder, mostly because he is from Newfoundland where my relatives are all from but I would have to say Zetterberg is the all-round better player. He might (and time will only tell) not have as much offensive upside as Ryder, but Zetterberg plays both ends of the ice. Ryder, from the limited games I've seen him play, is pretty one-deimentional. I'm sure though if I was a fan of the Habs it would be different.
Ryder has been a surprise with how well he's done. Last year, Zetterberg didn't really shock us much...we knew what we were getting because he was hyped up for a couple years before joining the team. Zetterberg has a creative mind as an offensive player but maybe not as much as Datsyuk. He's definitely a solid defensive center. With Ryder, he's played with some very productive linemates and he's probably made himself a Calder finalist for sure. We'll see in the next couple of years how good he is...he's made a whale of a first impression this year.