Some comments I've read around the internets about Doc Horrible's sing-a-majiggy's conclusion:
"Well that was quite a dickpunch."
"Is it wrongthat I got all kinds of giddy when I saw the Mutant Enemy logo at the end?"
"Yeah Joss, whatever. I think we're used to that by now. More to the point, yay! Dr. Horrible made it into the Evil League of Evil! :) I love it when people achieve their dreams."
"After Act Three, I feel cheated... annoyed... and maybe even a little angry that I gave this thing such high recommendations to friends and family based on the strength--and hilarity--of the first two installments. That was--no pun intended--a HORRIBLE ending."
"HO. LEE. SHIT. Joss, dude. Seriously. That's all I can say and I'm not even 100% sure what I mean."
"I gotta tell ya, this has been one of the most enjoyable pieces of film I've seen in quite a while."
"I would go so far as to call it tragic"
"Mr. Whedon, if you accidentally wander across this blog post on your journeys through Netland, I'm offering to come to LA and give you a really big hug and a blueberry muffin if you will, just once, not have one character in your work suffer horribly. I agree that it adds a lot to the impact of the story, but really, you're killing us here. You big, brilliant, disgustingly talented meanie you."
and the usual
"Joss is God"
I also read that there was some distaste for the fact that dr. horrible's sing a long blog website didn't have, you know, an actual blog on it.
and a Review/Interview w NPH: