Betterman is fantastic. It's one of my all-time favorite shows (but so were Evangelion and RahXephon, which apparently make me an elitist).
I will warn that it's not everyone's cup of tea, being very hit or miss. It's unlike just about every show I've seen, mixing elements of comedy, mecha, and horror in such a way that I can't really put it into words. It does its horror surprisingly well, capable of putting its characters into genuinely creepy situations despite their hardware.
But don't let the GGG link fool you. The two are nothing alike. GGG is great for capturing that corny old Super Robot style. Betterman is fantastic for its darker edge, which is more in the vein of more recent "in your head" shows like Big O.
I say check it out. It will be a memorable ride, if nothing else.