I don't travel too much (at least not where I'd see these being used), but went through a spate of train journeys a couple of months ago, and spotted several people with e-readers, these were all Sony's though, the obvious reason for that being their presence in a lot of Waterstones whereas the Kindle just hasn't been available, so it looks like the lead for the different readers really is different on both sides of the pond.
Back to the OP topic though, I've been asked about my CyBook several times (my wife says I should ask Bookeen for commission), but to be honest I always find it a pain, I'm happily sitting their reading I don't have any signs saying "feel free to disturb me I'm not really interested in reading my book anyway" on me and people feel free to interrupt me just to satisfy their curiosity, if I weren't so polite the response would be "p**s off and mind your own business" instead I have to waste a good 30-60 minutes explaining what e-ink is and how you can buy most of the books you can get at the book shops, when all I really want to be doing is sitting peacfully reading my book
Mark