(Spoiler Free Review)
Minor objectionable content (TV-14).
This show is a fine gem wrapped in a velvet pouch. Those diamonds are real, period.
Last Exile is a must watch for every anime fan. If you don't watch it, then you're missing out on a great story. It is fantastic! Truly one of a kind. The genre is steampunk with an emphasis on flight. Definitely a teenage demographic, but I wouldn't call this anime shounen or shoujo (more of a seinen). Continuous plot with many important events from start-to-finish and a clear goal in mind. That is extremely rare for anime these days.
Characters are wonderful! Also, there is massive character growth. You'll see them change right before your eyes.
This show was aired in 2003. Ironically, anmation and sound is better than some of the "newer" shows. Some older CGI, but still acceptable.
GONZO studios is really hit or miss. They have fantastic shows or junk, nothing in between. I'm happy to say that Last Exile is a hit.
There is a second season and a movie, but this review is only based on the first season (26 episodes).
All in all, I rate this show 8/10 -- Must Buy (5/10 is average). Just because a show is old doesn't mean that it is bad (e.g. Studio Ghibli). Give it a watch, you won't regret it.