I can totally get what you're saying. And, to boot, it really depends on whether you're looking for a wargame or an RPG. But, yeah, there's a bloody mountain of background material in Battletech. And, yuppers, I can see that as a huge turn off for trying to get into the game.
As a Battletech fan, I do have to say that the Catalyst Games stuff is very good. Their Basic Box covers the game pretty darn well and if you pick up one of the Tech Readouts (3025 is my favorite period - I have no love for the clan stuff that comes later), you're good to go for the wargame.
But, yeah, I can totally sympathise.
Cool, thanks. It is good to get some tips on where to get in and my group is looking for some new ideas to try out over the next few months until August.