I find it difficult to adequately describe how intensely I abhor this branch of the series.
1) The characters (except Gubaba and Sivil). From the generally over-colorful and outlandish pop-style to their mind-numbing reasoning. Then there's the premise; I believe if I tried to get in front of an elite US Special Forces group and a legion of Al Quaeda terrorists already in the midsts of a gun fight with a guitar I would have very little time to strum a guitar. Even if I could, I'm pretty sure the US would have me dragged into a very small prison cell and beaten with a rubber hose until I promised to never interfere with ANYTHING EVER again. Basara doesn't grow. Mylene is a 14 year old sex symbol. Ray seems like he has potential but it never develops. The quiet girl really should have been more of a Silent Bob character and said some pearls of wisdom... instead of just being quiet.
2) The red YF-19's FACE and any other vehicle that had a face that I might not be remembering. What age group are we trying to appeal to here? How much sake did they consume before they decided mechs with faces that were controlled via electric guitar were a good idea?
3) As someone already stated, the designs of the non-warships were just quirky. Again, seems like they were trying to appeal to very little children. The protodevilin fell into this problem too. Just plain strange designs. Battle scenes? I'm pretty sure I got to see the same battle scene about 47 different times. No, Basara's four songs didn't get old. No... not at all. Ooh, i love how they mix it up by having Mylene sing one of Basara's four songs every now and then. WILL SOMEONE PLEASE SHOVE A FRICKING KATANA IN MY G*D*A*N EAR??
4) The never consumated love triangle... wow, that's one way to really peak the stress level. Allude to an odd arranged marriage with a 14 year old and her possible crush on a possibly homosexual and quite certainly insane Basara... right... I really couldn't wait to see who ended up with her. And then, even though I didn't care, no one does??? Yeah, great job.
5) I felt like most of the 500 episodes were cannon-fodder just trying to move the story along and generally failing to do so.
The only redeeming qualities I found to this were cameos. I'm not sure if MacPlus came first but the mech's from that (since that's the order i saw it in), Max, Milia, VF-1, Exe, and anyone else I may have forgotten. There was some potential in the exploration of the protoculture but i ultimately didn't like the path it took. I've never shaken my head so many times while watching an anime. Argh, thank you for letting me vent.