I approached this episode like I have much of the entire season: this could be great, but it has the potential to be a sugary sweet mess. It certainly tended toward the former, but I think more from the fact that it was less about the music and more about the impending end of the season (i.e graduation). The music was worked into the plot well - although I'm not sure why they chose to try to capture the look and feel of the "It's Not Right, But It's Okay" music video with Blaine when they didn't do that with any other one.
There were elements that I didn't care for, especially the ending of the episode with the gradual group number on stage (since when were Glee rehearsals optional?). I understand RM's desire to add balance with Joe, to represent religious fans, but the dilemma with him and Quinn was a little much. Kurt and Blaine's relationship still puzzles me and the way it is portrayed (vis-a-vis Santana and Brittany) is bizarre: When they finally reconcile in Emma' office they just hug, no kiss. I guess America isn't ready to see two men kiss in prime time (but seeing two girls kiss is okay?).
Overall though the episode had a lot going for it. Well done!