You can use PDF with the Kindle. Of course Kindles are only black and white (actually e-ink). You'll lose the big feature of the PDF for your scans. I have a Kindle, iPad, and Android tablet. Of the three the iPad is the clear winner for this type of use. Its pretty zippy and the pdf-notes application (free) is very good for handling the large (220MB) PDF file that I have for my scans.