I've had a Sony Reader 500 for over 2 years. A great reader, lasted for thousands of hours of reading. I found with the Sony that I was turning the page every 5 to 7 seconds. I just timed a page on the DX. 50 seconds. It feels as if I'm reading a real book. I have way more... Time... if you will to think and review what I'm reading. More space on the page and more paragraphs to glance back at as I think through a passage. The annotation and highlighting feature is great too.... But the real book feel, thats the number one reason I love it. The text is much sharper and darker, the background much whiter also. The wireless in device shopping is wonderful. I like the Accelerometer too. You can disable it easily enough with a single click. The Dictionary I use constantly. The internet experimental features not so much although I have downloaded a free book or two from Manybooks using the DX. I don't have a great need for PDF's but I do have a complilation of Robert Frost poems in a PDF form and they display wonderfully. I downloaded a few newsletters from the website EPM and they read just fine. Nice and bright.
http://www.epm.org/home_mainPage.php
This business about it being 'heavy' or 'too big' in my opinion is nonsense... Well ok.. not nonsense because I understand this is an issue for some people but for me its not. In the slightest. to me it feels light as a feather and clean. Thin and very sturdy..