I saw prometheus with two friends, one of which was quite a big alien fan although not an obsessive like me, the other had seen the films a while ago but was not really a fan at all.
Both of them walked out basically saying "Pretty good, no as good as alien. Too hyped. 3/5" which was pretty bloody unfortunate as my reaction more along the lines of "F*CK YEA! IT'S THE FOLLOW UP TO ALIEN I'VE ALWAYS WANTED! WAY BETTER THEN ALIENS! DID YOU SEE THE BIT WHERE..."
Which was of course immediately met by massive "WHAT"s and other confused gestures and was immediately told how apparently wrong I was. After a rather wrong period of debate, discussion and just plain arguments they said that they preferred "The Avengers". So naturally and real casual like I ran them over with an APC and kept shooting them with a flamethrower until they stopped twitching and died. Ok that last part didn't happen it was only what I would have done, the rest is 100% true though.
Saw it the next day alone, although the cinema was packed despite being 11.30 in the morning on a week day. The story seemed better second time round however the projectionist f*cked up and the 3D came through funny, was fine at midnight. First time I saw a film in a cinema alone, actually preferred it to in a group, I'll need to start doing it more often .
TL;DR: I, the big alien fan, loved it whereas the less fan like 2 enjoyed it a lot less.