I won't write a the detailed description since other people did it already. I will only add that this seems the perfect tool to reproduce mecha anime action in a fast and true-to-the-genre way.
I am in the process of preparing a mecha sci-fi campaign based on the Universal Century timeline (Gundam), and I have been considering the options as to which game to use, the main contenders being Mekton Z and Jovian Chronicles.
Well, if Mecha here will allow customisation of mecha and characters in a reasonably complete way, it will be my game of choice replacing those classics above. It's THAT good! Brilliant game.
[5 of 5 Stars!]