I've been to 2 NHL games. I sat near center ice and from behind one of the nets. I know I'll be in the minority, but I enjoyed the seats behind the net more than I enjoyed the center ice seats. I felt like I could see the puck movement better.
+1 ... My friend has Coyotes season tickets 5 rows up behind the goalie. It's an absolute blast seeing the action come at you, especially those shots that go wide off the glass in front of you. It's tough seeing he other end of the ice but it's a non stop up and down sport as it is. And again, agree that you can see the puck movement better behind the net.
I've heard sitting on the ice on the sideline portion of the rink makes it impossible to see the other end of the ice, with the angle of the boards plus the benches/penalty boxes.