I have a good collection of ebooks in ePub format, because my only dedicated ebook reader is a Sony PRS-600. I do most of my reading these days on an iPad, but I'm considering getting a Kindle 3. I know that some books I've converted through Calibre, namely PDFs, are difficult to read because of formatting. Is the Calibre formatting from ePub to Kindle format any better? I know that some books, the ones I've purchased on Smashwords, can be downloaded again in mobi format for the Kindle (good reason to choose Smashwords over other distribution methods!). Anyone have firsthand knowledge of ePub to mobi conversions?