The comparison would be with the PocketBook Inkpad 8 inch, which seems to do far far better in direct comparison reviews. Higher res and faster. But about £150 and only available from Europe at the moment (Conrad UK used to have it but seems to be out).
There are two 10 inch readers which seem to have their different merits, the M96, a pure Android reader, but lacking a high res screen, or the Hanvon WISEreader E920, which has high res screen but does not seem to be plain android. These are around £400 on Amazon.
There is also the sony, but while its huge and has a high res display it is pdf only and very very expensive.
What we need is a high res 10 inch screen, plain android, with a fast processor. Or maybe, with the new Intel stick computer, we would be OK with an e-ink monitor and run it off one of those?
The problem with current ebook readers is not so much epub or mobi - the Kobo Aura HD seems to do fine with them. Its PDFs. Lots of stuff is only available in that form, and the Kobo 7 inch screen though very nice is just too small, and it simply will not display scanned PDFs properly at all. Well, if you are trying to carry around quite a few technical articles and manuals, this reduces you a conventional tablet. Which is fine, but its tiring to read and has short battery life, and its another thing to load down the travel bag.
Maybe it is too small a market. Would have thought not. Large numbers of technical, legal and financial people need this.