As I mentioned previously, I like Motion's LS800. I'd like to see what folks who are more Tablet-experienced have to say when they get their hands on it, but
reviews so far have been generally positive. The main complaints seem to be battery life, heat and price.
We'll have to wait and see what battery life really turns out to be in day-to-day use. I was surprised with how small the battery seems to be. It looks like it would make a lot of sense to continue the battery around underneath the device. Maybe an option is the Electrovaya PowerPad 80 that has an almost identical footprint, and its 80WHr capacity should give over 8 hours runtime.
I won't comment on price (all of these things are too expensive to achieve major market success right now) or heat (it's fine as long as it isn't likely to start a fire), but I do want to discuss screen size. Many of the comments I've seen (from people who haven't actually seen one) are disappointed with the selection of SVGA (800x600) instead of XGA(1024x768). I was in this category, too (note my requirements), but decided to see whether I could live with it.
First, there are two separate issues here: how much can you get on the screen, and how big, clear and legible is it? To look at the "how much" question, I set my iBook to 800x600 and did some of the things I'd expect to do with the tablet. I could actually display an entire page (8.5x11) from a PDF and read it in portrait mode without scrolling (avoiding scrolling on multiple axes is the key -- ever tried to use Acrobat Reader on a QVGA PocketPC?); not sure I'd want to do much of this, though. Web surfing wasn't too bad. I'd probably be fine with how much you can get on the screen at once, again considering that reading rather than creating information would be the main use.
To judge the clarity, I next set the iBook back to 1024x768, but left the windows at their 800x600 size. This resolution gets the dot pitch closer to what we'd expect on the LS800. I could still read the PDF. Now, I suspect the actual screen on the LS800 would be a bit higher dot pitch and a bit clearer (being four years newer technology and designed to be viewed from multiple angles). For reference, the iBook's dot pitch is something like 105dpi, and I estimate the LS800's at 119dpi. Note that an 8.4" XGA screen would have a dot pitch around 152dpi! This would give you a crisper experience, but you would likely have to reduce the amount of information on the screen to something closer to SVGA levels (or keep a magnifying glass around).
Overall, I think this is probably a good design decision on Motion's part, and comments from people who have seen the device seem to bear this out.