So... I finished Last Exile 10 minutes ago.
First thing's first : the story. The action takes place in a steam-punk/SF world and the details in the show make the good use of these elements. In the first episodes you can see a lot of flying machines, strange clothes and all sorts of locations that characterize a steam-punk universe. All of this is very well represented with beautiful animation. Actually the animation is the best part about the series. Aerial battles are amazing and the vanships are very detailed. Unfortunately I only got to see this in 720p on a 17' monitor...but it must be a real eyegasm to see it on a big screen TV. I will do this sooner or later.
Sound and characters... well this is where the bad things start to show up. I need to listen to the full OST but the opening theme is really good. There is a certain "fighting/dancing scene" where the music is memorable. Moving on to the characters... well some of them were great some were just to fill up the empty space. The only noticeable thing is the close relation between Claus and Lavie. Sophia is boring as hell, Alex is dull once you see that all his lines are in the same area and Mullin... well let's just say that he is one of the characters put in just to fill up the empty space. He has no actual value for the show.
As usual, I keep the bad things for the end. First of all, the steam-punk theme was a great ideea and it was very well made. Why did they have to screw it up with the SF...? There are some huge holes in the plot and the fact that you only know detailed stuff only about Lavie and Claus does not help at all...
In conclusion, I think that Last Exile was made more for the eye and less for the brain. If you can ignore the weak character design and weak story and just be able to be amazed of the beautiful animation and sound, than this is a five star anime. It's awesome. However... I can't do that. With all the stuff lacking I can only give it a 6.