So I haven't experimented with the battery yet, but my understanding is that the battery life is only improved with wireless on -- they're estimating now 1 week instead of 3-4 days, but still ~ 2 weeks with wireless off. I agree the battery life with the wireless off is stellar -- I thought it was rather unfortunate with the wireless on. I was able to finish most literary fiction books (books that are typically 250-350 pages in hardcover) without recharging. Hopefully to me the update means I can now leave the wireless on, and maybe have to just have to recharge once during each book. Once a week is bearable; I just have to remember to do it.
I did the update manually (thanks for the clarification -- I didn't see that on Amazon's 2.3 page) just now. I did try uploading a PDF to the 6" Kindle 2 and wanted to share some results.
Most of the features seem identical to the way the DX works. PDFs should be placed in the Documents folder and then appear as Personal Docs (so if you put your Kindle in "Show Books" mode it will hide them conveniently). There is no zooming, nor is there annotation. There is keyword searching. Page turning is actually quite fast at least in the example I tried. Actually, at the risk of sounding like an old Safari thread... page turning might be slightly faster even in books compared to 2.0.3, which was previously on my Kindle.
Interestingly, as a testament to the grey scale, aliased rendering, in good lighting, two-column scientific journal articles are actually mostly legible even in portrait mode, although I would think landscape mode would be the defacto choice, since it's still quite the eye chart. In landscape mode the full document width is shown and the prev/next keys scroll down through the page. Here is a journal article in typical format presented in both landscape and portrait.
Overall, so far I'm quite impressed. Now I'm going to leave the Wifi on and see how the battery does.
