Tablet Buying Guide by Joshua Soule at Spuyten Duyvil Library
Keep in mind that if you have a smartphone (iPhone, iPod Touch, Android) you already have access to many of the e-reading tools on this site.
Consumer Reports Buying Guide 2014 available in MasterFILE Premier.
Academic Search Premier to access articles from Consumer Reports.
Other websites with reviews:
From the Electronic Frontier Foundation: "Who's Tracking Your Reading Habits? An E-Book Buyer's Guide to Privacy, 2012 Edition"