As the proud owner of a DR800S for about six hours I have to say I'm really impressed by the text re-flowing. Whilst it's not going to help documents with technical notation, diagrams and illustrations, it's much better than I thought it was going to be and some of the academic journal articles that I was concerned about read really nicely. Don't get me wrong, if zooming can be implemented I think it should be, for all the reasons that have been stated here.
Now that I've got folders sorted with the help of people on this forum, all I need now is annotation and I will be a very happy chappy (relatively speaking).