Agreed on Calibre -- and it's free!

Not sure how well the epub will render on an eInk book reader. I use Bluefire Reader (free) on my iPad and on my Windows PC. I've also been known to use the built-in Preview utility on my work Mac for this as well. All of them render the epub very well.

I upgraded to General using the ARRL ebook. I'd like to upgrade to Extra one day but life is very busy right now.