OK, I installed the v2.1 on my V811. I folllowed iiDiabolusZz' updating and rooting routine as described in this forum, which worked fine. Apart from loosing all apps and data with the update i can't see any striking differences, except for the addition of one or two additional chinese apps. Perhaps it feels a bit (once more) snappier now when switching on from standby and accessing wireless networks. But that may be a subjective impression. No problems otherwise.
I'd estimate that my v811 lasts around 4 hours of gaming. I've never tested for just browsing but I'd assume it would be about 5 hours. It's not as good as my Asus transformer but I think its pretty reasonable. I'm actually selling an v811 on ebay at the moment but I'm in the UK so not much help to you.
