Kindle DX
I just got a DX for Christmas for the purpose of displaying government plates for IFR flying. Without question, it's beautifully suited to the task, and PDFplates.com makes it easy.
Personally, I wasn't interested in any system that required scrolling to view a complete chart. Rather than trying to scroll during an apporach, I think it's better to just go to the NACO website and print off the plates you think you'll need for a given flight and do it the old-fashioned way.
The Kindle DX does a great job of displaying full-size plates, but in the interest of full disclosure, I have a minor complaint that users should be aware of: after 20 minutes, a "screen saver" kicks in and switches the display to a nice black and white image of a famous author. Restoring the apporach plate takes some waiting and some button pushing, and unless you can fly an approach in your sleep, you'll likely have to go missed if the screen saver kicks in within the outer marker and you need another glance at the plate. A best practice is just to make sure to click a button or two before being cleared for the approach to ensure the plate will be visible for the entire procedure.
Ideally, the unit would just maintain the approach plate image even if the unit goes to sleep. To me, this is the ultimate in EFB fault tolerance, and I believe several DX users have requested that the screen saver be eliminated for this purpose. Be aware that hacks were available to disable the screensaver in earlier DX firmware versions, but none is availabe for the latest firmware. In general, hacking a Kindle can create compatibility issues when new firmware updates become available from Amazon.