I mean, the people making them, for one.

Personally, I love Mekton Z. It shares a lot of mechanics with old school cyberpunk if you ever played that, and has an awesome and expansive system for building an entirely custom mecha. I still use it with a ton of homebrew conversion rules for my World of Darkness campaign (why are Mecha in my WoD game? Don’t ask, it’s complicated.) It’s got a lot of the same intricate style and flare as cyberpunk 2020 and it’s chrome books, so if you’re into that, highly recommended.