The newer version with the torx pivot is 100% identical to the old version except, obviously, it has a torx pivot. As for which model you should get, you should be a little more specific on what you want to use it for, as they are actually very different knives with different applications in my opinion.
I've never owned a G10 Manix, but I did own a blue Manix 2 Lightweight with a torx pivot. Good knife for the money; good size, great ergos, and decent materials. The handles were cool looking but in-hand they didn't feel that great. The steel seemed good, never had any problems with it. Locking mechanism on mine was gritty as sin, but I think mine was a fluke. Overall, I liked mine, but if I had the chance to do it again, I'd pick up a Sprint version instead.