Thanks for the quick reply guys!
Ideally I would like to buy a high resolution 10" tab like Nexus 10 for reading(PDFs) but at the moment I dont have the money to buy it. And anyways I need a dedicated e-ink device for epubs/mobi. As for reading graphic based PDFs on 6" eink goes, I'll have to be a bit patient(panning, zooming and potrait mode) but thats compromise I guess.
And I would've selected PRS-T1 for the PDF capabilities but no backlight. I plan to read a lot in the night and the lamp case design looks cumbersome.
Just to make it clear, I don't have to set any account with Amazon to make the device work, right? Because I'll be opening the box in India.
Also, do you guys get a 'low memory warning' when you open a graphic based big PDF file?