I've been waiting for this since November and at last it arrived today. Like some folks who have been waiting for the NEX7,
First impressions: A little bigger than I thought it would be, but it works like a charm. A couple of bad photos (hand held 1ds2 with no IS, to lazy to set up studio lights excuse) show the size and the bottom as well. It does have a tripod mounting hole but the width is slightly larger than a JTec L plate so when mounted in a Arca type clamp the adapter has to be outside the clamp. The JTec bracket is about 1/8" to narrow to fit on the adapter (rats) so here is hoping that RRS will give us a nice bracket that will tie the two items together. The only downside to me is there were no caps included but the presentation box looks very nice and the adapter is well protected by foam.
How well has this been holding up? I haven't seen many reviews on the net. One person did a video review with this adapter on the NEX video cam. One of the comments in the dpreview announcement said it didn't work but the next day it worked for 30 seconds.