Yeah, they went to Mechwarrior 3 in 1999. The Classic Battletech RPG book is just an updated version of Mechwarrior 3. It's mostly the same just with the errata from Mechwarrior 3 and a few other small things IIRC.

No, idea. Some people like it and some people don't. I think it usually boils down to if you like the life path system or not.

Better ones out there though unless your dead set on it being Mechwarrior.  My personal favorite is the Alternity system.  Theres a few different universes that go with that also.  Ones called Gammaworld.  Its sort of like fallout, post apoc etc with mutie animals and the like.  Another is stardrive, which is a "space opera" genre universe.  I love both.  Theres a few others as well.  I've played 3rd ed. Mechwarrior and Alternity and I prefer the alternity rules by far.  Might be hard to find a actual copy of the books though other then online.  I know some of them are available for free.  A old book seller may have some though.

On a side note of nostalgia did anyone else ever play Traveller?  I loved that one too.

I've played MW 3rd edition for about 4 years, and I loved that system. It's intuititive and uncomplicated, giving you more space to focus on the story and the character developement. And the 2x d10 system I think is brilliant. Compared to DnD that we play now, my character is already lvl 9 and i still can't figure out the mechanics, haven't been able to lvl up without the GM practically doing it for me, which does damage the overall feel of the game. As for the new CBT rulebook, it feels kinda stiff, so we stuck with 3rd edition until the GM ran out of ideas (boy that story lasted longer than I would have imagined)