The universe of the future is divided between the Earth Alliance and ZAFT. After a year of war, ZAFT attacks the neutral colony Heliopolis to steal five prototype mobile suits. The mission is a success, but a young man named Kira stumbles upon the fifth Gundam, and he may be the Alliance's only hope...
Two best friends sharing many memories together meet again on opposing sides of the battlefield, neither right or wrong and fighting for their idealistic beliefs. Did I mention both have awesome music and feature mecha battles?
Both include a situation where war is taking over the land (though Gundam SEED is war of space and Break Blade is warring countries) the ideals of the lands are similar in that Heliopolis and the primary country in Break blade both wish to be neutral and maintain peace, however events lead to robotic fighting where there is one special (or multiple special in case of Gundams) are relyied on to protect or initiate the peace in what seems to be an unending war. In both of these series there is drama of friends fighting friends and even situations where the enemy becomes a friend. They both attempt to show the reasons each person has for fighting and how sad it is that the majority of the people fighting are doing it based on beliefs that are not true.
Two friends on opposite sides of a war and Mecha battles are two elements that both of these anime really focus on. If you liked Break Blade, I recommend you try Gundam Seed. It has the same themes with slightly better characterization.
In 2010, the Britannian Empire enslaved Japan using powerful mecha known as Knightmares; in the aftermath Japan was renamed Area 11, and its people began a hard and terrible existence. Lelouch, a Britannian student living in Area 11, has grown up hating the Empire and everything it stands for. One day, in the middle of a terrorist attack, Lelouch meets a mysterious girl who grants him the ability to control minds. Can he use his new power to fight for freedom, or will his hatred twist his good intentions into mindless acts of vengeance?
Although Break Blade is still being released (and I have not read the manga), so far I think people who liked one of these should consider watching the other. They both involve a lot of action and a war, using mechas as their means. The relationships between Lelouch/Suzaku and Rygart/Zess are quite similar, in that they are comrades turned enemies because of a feud between their respective countries. Also, generally, they are both pretty fantastic :)
You probably will like both of these. I'm not huge mecha fun because most likely anime shows that feature mecha's as their main feature lack in story. Do not worry! The strongpoint of these shows is very unique characters and their abilitis that are absurb in the world.
Hopefully you will come to like both of these series because they're very nicely made and should be watched even though they have mechas. Maybe I should give up this mecha fear of mine but I have seen too many bad bad shows. It is very nice to notice that some of them are very good.