My ds, who's in year 5, has had an Alphasmart for over a year now and is now hopefully in line for a laptop, after some pushing from his teacher and recommendations from the EP.
He doesn't have dyslexia, but has fine motor and other issues with handwriting which were holding him back in written work - basically he got to the point where he just refused to write.
His teachers came up against problems with using the Alphasmart because of the small screen and are finding this is a problem more and more now he's producing extended pieces of writing.
My ds has AS and we've also find it nigh on impossible to get him to revisit a piece of work for editing and laying things out properly. To him, once he's finished typing a piece of work, its done and dusted. This is a real problem with the Alphasmart, because with the small sized screen he can't see enough of his work to be able to set it out nicely on the page and forgets to put in paragraphs etc.
Its also a bit of a pain having to plug it into a computer to download then edit the work, as its an extra leg that takes additional time and of course relies on access to a computer whenever its needed.