reading textbooks on an electronic LCD display is nothing compared to the user experience gained by reading it on an e-ink designed electronic reader like the Kindle and Sony PRS series.
The Sony PRS series are MUCH more elegant than the kindle, much cheaper ($275 Vs $>400 streetprice), & is much better (reads pdf, has larger memory, one can convert their own books at home, longer battery life, even some games available; but the kindle has a keyboard and G3)!
Also Sony sold more Sony readers than Amazon sold Kindles.
Sony's longer in the business than amazon.
The only bad thing is Sony has about 60.000 books on their store, while amazon has nearly 200.000 books for sale.
Good thing is that nearly 8.000 free books can be gotten for the Sony, while it's somewhere near to 1.000-2.000 free books formatted for the kindle.
Apart from their own electronic book formats and regular .txt, the Kindle can't read many formats, and they need to be converted.
Sony can read pdf files.