The problem with DRM Free ebooks is finding the good books, as there are some not so good books around. This also applies to DRM locked ebooks – eg. Amazon.co.uk (especially their free / low-cost self published books), although with DRM books you can turn to the mainstream press for reviews of the latest bestsellers. It does mean that some really good books that don’t get a mainstream publisher may not get the publicity they deserve.
These are just some of the books I’ve read, but they all have one thing in common. They are all available without DRM, so you can read on any ebook reader and on any PC / Tablet / Netbook regardless of the operating system or reader software available.