finished phase 1 in my marathon (well, technically its not a marathon if you dont watch all in a row, but anyway), I actually liked Thor 1 a heck of a lot more than I remembered, and there's also a lot more mystical stuff than I remembered. Frost Giants are a big part of it and they are very faithful (except in size I guess). Captain America The First Avenger tho, is bloody fantastic and I always pegged it as one of the worst in the series. How wrong I was, I absolutely loved it this time around. I didnt even remember Bucky was in it, same actor and everything.
Avengers on the other hand, im still so-so about. It's cool to see them all come together, but I still think the movie isnt very good. For all the shit AoU gets, I dont think the first one is much better tbh. And the suits are awful, both Cap and Thor.