I absolutely love Gundam Seed. One of the best animes I've ever watched. Gundam Seed Destiny started off great, but ended up pretty dull. Unlike Gundam Seed, which just kept getting better and better, Destiny only got worse and worse. There where a few good episodes towards the end, but overall it just ended up being decent. Destiny lost too much focus on certain important things (like its main character), and there where a lot of scenes that just seemed to be randomly thrown in for no reason. Also, the ending was kinda dissapointing. So yeah. The first 25-30 episodes are great, though.

Also, Raww le Klueze is by far one of the best villains ever. He's my favourite anime villain and another reason Seed is superior to Destiny.