From the weights on Iplay's site, it looks like the frame and wheels together will be around 150 g lighter. I guess the tires will knock off a bit as well, but this seems pretty close to insignificant. I haven't thought that my -057 had any problems with maneuverability, so to paraphrase CD, I see no reason to want anything but my Chiner.
Besides, Chi-27.5er just doesn't roll off the tounge