Mechwarrior 4 was good in my book, they revamped the old models and made some new ones. Black Knight was a let-down on the storyline, and Mercenaries was great but short.
I've played all the them going back to the NES Battletech. I read the books too they were very well written, it's what got me into Sci-fi.
I always have had a soft-spot of fusion powered walking deathmobiles.