No, unfortunately. Most of the videos going around (read: all of them) are from MWC where B2G was demoed.
The development group is VERY active on IRC and there was some chatter at the time about that. Some of the slight lags in the demo were actually parts of the CSS transition they use (originally intended to avoid accidental swipes when they wanted taps) and was tweeked to be much better not long afterwards.
More recently there have been significant improvements in the actual CSS animation on the gecko side (improvements which will hit firefox in the future) which means everything feels even faster and more natural.
At this point B2G is making significant progress _every day_ so about the only real way to get an up to date idea of how it runs is to either read the github commit log frequently or put it on a device (and currently that means a GSII)
