I handled one of these today at Yodobashi in Akihabara. Its OIS is amazing. I'm sure I could smash through 1/20 and lower exposures inside with no problems at all. Manual focus was lousy: slow and heavy and required many turns of the focus wheel to reach either extreme. AF seemed to lock in pretty fast, but then again, with a low-res EVF, you can't eye-ball it to be sure it is locked in or not.

The short: feel/speed of MF in comparison to a 70-200/4 or 2,8 from any major manufacturer was very, very poor. But OIS way, way better. Size was comparable to its FF 70-200/4 equivalents from Nikon or Canon.