My biz partner (also in China) and I tried out the recent "video call" feature for the first time earlier this week during one of our evening calls because Skype was being annoying. I had noticed previously, but dismissed it as something that would surely be a let down. Furthermore, I simply don't like the idea of video calls (we're not living the Jetsons' Era yet, after all... as soon as I get my first robotic ayi, I'll succumb to the video thing).
Anyway, I took the plunge, and was simply blown away by the quality... AMAZING. Furthermore, I learned how to disable video within the first 3 seconds... so no problems there.
I would probably only use this function when on wifi because (based on the video/sound clarity) I'm guessing the data consumption is non-trivial.