Mostly it's a limitation of e-ink, mlkmnz. The material can refresh at two rates, .5s and 1s -- the faster leaves more ghosting, apparently, so everyone seems to be going with the 1s.
In some cases (depending on which vid you were watching), there's some additional time needed to render the page before the e-ink
starts doing it's refresh cycle.
That's for now.
iRex has made some good progress in speeding up their rendering waits (largely by pre-rendering, as I understand it), and we're waiting to see what the other pending products do with it.
Presumably, future generations of e-ink will decrease the refresh delay.
For the moment, consider it in context of how long it takes you to turn a paper page to get an idea of how long it really is in practical terms. And remember, e-ink pages never stick together.
