If you want dual audio, then go with a4e. If you want japanese only, KAA is a lot easier to find with a stronger seed pool. Quality should be similar, although KAA obviously uses a higher video bitrate since the file size is almost identical.
Most people have seen the show, so if they did look at the thread without posting, they were probably thinking the same thing I was. Download the first episode of each and decide for yourself if the anidb ratings mean nothing to you.
If you'd prefer fansubs, Ani-Kraze still tracks the torrents for their version, albeit with very few seeders. They've done some great work in the past, so I'd go with them if official subs aren't your thing. Last Exile was; however, a Pioneer production, so expect very high quality from the official translation.
