Edit after vol 6:
Unfortunately, the manga has gone downhill from promising starting point toward generic shounen. Originally promising characters haven't been developing, but rather regressed toward stereotypes. Main cast has been joined by a dozen of side characters, who so far haven't been playing any significant role whatsoever. I'll keep reading, but I've reduced my originally high rating accordingly.
First look after 2nd volume:
Even though Break Blade is classified as Shounen in Manga Updates' database, it has rather subtle, mature and contemporary themes in characterization. This was a pleasant surprise for me.
Take for example how Lygato is shunning away from world due to his self-deprecation, Hozul's yearning to escape his responsibilities as a monarch, Shigwen's escape from her withering marriage through dedication to work. And of course Shigwen's subdued feelings towards Lygato. I love the way how these things are often conveyed in a somewhat subtle (though sometimes a bit underlined) manner: gazes, daydreams, expressions of face and stature.
And all of that comes with the other good stuff (in my book), which are action, mecha and a fantasy setting. Actually, these things remind me a bit of Xenogears... I hope the story gets as deep too. It would be exhilarating to have both style and substance in the same package, instead of mere brainless "WE NAKAMA! GO KILL BAD GUYS WITH NEW SUPER ATTACK!"-escapism that many Shounen series regress to.
Art seems passable. Backgrounds look often rather simplistic. Mecha designs appear to be neat, but it's kinda hard to tell for sure from the scans.
To sum it up, Break Blade (or rather Broken Blade) seems to be quite a promising series. I've only read two first volumes, but it has a very polished and well thought-out feeling. I sincerely hope Break Blade keeps going strong.