[citation][nom]teh_chem[/nom]I think widescreen tablets are a terrible design for ergonomics. I actually like the aspect ratio of the iPad, and I dislike the aspect ratio of my Transformer. If you do any work in portrait mode, it's fairly awkward to hold and use at times.The thing that gets me is that while 16:9 or 16:10 are the "standard" current common aspect ratios, a lot of movies/videos are NOT that ratio. [/citation]
If you compare to the written area of a sheet of paper (i.e. subtract the margins), you'll find the 4:3 and 16:10 aspect ratios are both about the same at reproducing letter-sized paper. For A4 paper, legal-sized paper, 3:2 DSLR photos, and movies, 16:10 has less wasted screen space than 4:3.
4:3 is only wastes less space if you scan an entire sheet of paper (including margins), convert it to PDF, and display it on the screen. But then you're looking at a 9.7" version of a 13.9" page. So a closer reproduction would be on a 14" tablet. You're better off cropping out the margins when scanning paper, after which 4:3 wastes as much space as 16:10 for letter-sized paper.
Personally I work mostly with DSLR photos, and vastly prefer 16:10 over 4:3. Most artists probably prefer 16:10 as well since it's very close to the Golden Ratio (1.618).
OTOH 4:3 seems to work better when browsing web pages (at least after Apple upped the resolution - the low res screen of the iPad/iPad 2 sucked at 4:3). So if all you ever do on your tablet is browse the web, then I can see that being better.