Bought these glasses for my Sony 40NX723 because Sony don't think the should supply glasses with their 1400 pound 3D televisions.
The glasses are actually rather large. Could easily be worn over smaller prescription glasses. They are quite light, but can still irritate the bridge of your nose (if you have a massive nose like me that is).
They charge up very quickly. 30 mins on charge with give you 30 hours of use, or you can charge them for 3 mins for 3 hours of use.
The TV detects the glasses and they power off with the TV.
The 3D effect that they create has been a mixed bag so far. i've watched the 3D clips that are streamed to the TV and also tried a couple of PS3 games (Wipeout HD and Super Stardust HD). The games were good, but a few of the clips didn't really seem to take advantage of the 3D. This is probably down to the content though, and not a fault of these glasses.
I hope that in the future 3D glasses will be a little more refined.