Very nice Supes pic! There's one thing I noticed, though, and I've seen it in the last few of your pics, is that you're starting to emphasize the lower lip on the guys, and it kinda looks like they're wearing lipstick. Wolverine's face in the panels on the previous page has it too, and it's something that immediately sticks out to me. I think it may be because your faces are so expressive that anything out of the ordinary really throws me off.
I think you can get away with just that little line at the center of the lower lip to express the fact that it's there, but not so much that it outlines the lower lip. You went much lighter with it in the panels of your comic and I think that it really helps when the male characters don't have a fully defined lower lip.
sequentials are a very interesting art form. it's more than just making pretty pictures. it's almost like storyboarding (telling a story) but you also have to design the panels to flow well.
I have a challenge for you. 
t: The other day I read the article about a potential Batman/Superman crossover movie, and I thought how cool it would be to see them flying through Metropolis or Gotham side by side, with Bamtan in the Batwing.....so I went to google and discovered that no such image exists.
