I've played a very broken version in which we didn't know all the rules because they literally have rules for everything and that's just a F-ton of reading. It was fun though.
I've wanted to play Battletech, but never did have the money to spend to get it for myself and none of my friends played. I loved the Mechwarrior video games. They were my first exposure to the world. I've read a few of the novels.
I got into the light weight rules, AlphaStrike, last year. I think I prefer Word of Blake forces. Played on occasion in the 90s. Played all the pc games. Never played the RPG.