It's time to report back.
Based on your replies and a little online research, I decided to buy the Onyx Boox i62HD. The reasoning is that the majority of people into academics suggest using a tablet and, since it was likely that even a 9 inch reader might not be up to the task, there was no point in paying double price. Thus I settled for a good 6 inch reader which, at worst case scenario, would be a quality general purpose reader and would allow me at least to do some of my research reading.
From what I see so far, it seems I made the right choice. On the positive side:
- The 1024x765 screen is really outstanding and allows easy reading of small fonts. I compared it to a regular 800x600 screen, and the difference is huge. If the font of a pdf is relatively large, just cutting the margins is enough to read it - it looks just like the same pdf if you print 2 pages in one A4 page, but with a greyish background.
- The firmware includes some extremely useful tools for annotations and highlights, as well as browsing and exporting them.
On the negative side:
- While you can scribble notes, it's not practical because of the screen size and touch recognition technology. It seems that this feature is actually useful only for the M92.
- As you all warned me, e-ink is slow. Not terribly slow, it's quite good for reading and low pace studying, but I don't think it's up to the task of working with dozens of articles at the same time, when you're preparing a work of your own.
All in all, I believe that the Onyx i62HD was a good compromise, considering that actually there's no perfect technology for what I need. The Onyx M92 would be somewhat better, but not good enough to justify the cost, while I'm avoiding the tablets because of the LCD screens. For the time being I'll be using the i62 for some of my research, and I'll be patient until the technology is good enough to completely replace paper for people into research.
If I get some time, I may write a proper review of this reader (since Onyx i62 reviews in English are rare).