I think it's a technology that fills a niche that LCDs or OLEDs won't fill for a very long time, if ever.
EDIT: Something more recent - http://www.youtube.com/watch?v=ag4HGceyVik . The colours seem to be lacking contrast but I'm sure that'll be improved as better filters are developed.
Mirasol and the like seem to be providing quite a good compromise - http://www.the-digital-reader.com/2012/01/01/review-kyobo-mi... That particular reader has the problem of not being as polished as the Kindle but it seems that the screen is rising up to the expectations.
(I think the problem is actually with page turns rather than the pixels; turning pages on the Kindle Android app is very flaky. On the physical hardware, it works much better.)