I've been interested in the various 'Mech games for a long time, and I've even owned several copies of different Battletech rulesets and starter boxes. I've been on a bit of a 'Mech kick lately as I've dug the Mechwarrior 4 computer game out of my footlocker and started playing around with the campaign game. From playing that I've branched out into once again researching some tabletop games featuring big stompy robots.
On the Battletech side of things, I believe a new Master Rulebook of sorts has been released in the last few months. The Battletech universe is interesting, and I like the customization that you can do with the "character sheets" for the Battlemechs. It seems to lend itself well to a campaign game in which a player could level up his pilots and salvage gear to upgrade his 'Mechs. On the downside, that nitty-gritty level of detail also is rumored to make the game play very slowly. I've also been browsing photos of the miniatures that are available, and a lot of them look quite dated. I think the miniature line could stand to be updated a bit to make the minis look more modern and mechanical.
Reaper just came out with version 2 of their CAV rules. I downloaded the PDF for them and I've been looking through it as well as browsing the Reaper catalog to see what the minis are like. I think the minis look a lot nicer than the Battletech minis. As far as the game goes, each miniature has a card that sets out in-game abilities, stats, and damage track. So all figures of a certain type will have the same stats. There's no real room for customization or individuality, aside from a few upgraded abilities you can purchase with your army points. This greatly speeds the game up at the cost of detail.
I'm still not sure if I want to get into either game system, but at the moment I'm leaning toward CAV, simply because it is unlikely that I'll find players in my area and I think I'll enjoy painting CAV miniatures more than I'll enjoy painting Battletech minis.