Amazing episode. I nearly stayed silent on this site last night because of it. It made me incredibly sad and seeing my favorite TV cast mourning gave me a different perspective on life, even if it was just for a few hours.
Everyone did some amazing acting in this, everything was pretty believable. Someone that surprised me a lot was Carol (Finn's mom/Kurt's stepmom/Burt's wife) and how she talked about Finn's death from a parent's point-of-view. Beautiful stuff.
Anyways.. this is easily in the top 10 Glee episodes out of them all. Probably song-wise as well.. the selections were spot-on and were all sung wonderfully as well.

Props to the whole cast and I'm really glad this is doing well on iTunes for a change.