To begin from the end, I can be as much of a snob against English dubs as the next guy, but I have to give credit where credit is due. And Manga Entertainment gets full credit in my very cooked books on this one; of all the anime that I've viewed over the decades since "round eyes" actually got a choice between subbed and dubbed, only two projects come to mind with English tracks that either rival or surpass the Japanese originals, and Gurren Lagaan is one of 'em. To its credit, Manga Entertainment has assembled an excellent English speaking cast to give life to Gurren Laggan's vast and varied cast. As for the animated property itself, I have to say that -- to the nearly four decades old tradition of Japanese anime shows that feature humongous human-powered robots such as Gigantor, Mazinger Z, Giant Robo and Neon Genesis Evangelion -- Gainax's Gurren Lagaan is a stupendous addition to a much-beloved tradition. It is, bar none, the very best anime in this sub-genre to hit the small screen since Neon Genesis (also by Gainax). Boasting space-sprawing adventure, eye-popping visuals, mouth-watering "fan service," and jaw-dropping battles, this is one anime show that has it all. So if you like giant robot shows, you might end up loving Gurren Lagaan, because it is bigger, better and badder than anything else in its weight class.
I now won't be leaving the house for a few weeks, and I blame you. :D