Thanks for the quick feedback. I convert my eBook formats back and forth too, but have never tried anything other than a novel, which is usually 99% plain text. I didn't know how Calibre's converter would work on picture intensive stuff like this ARRL manual. Glad to hear it does OK. I prefer the plain-jane eInk book readers like the Nook (or basic Kindle) for reading. My Kindle Fire can stand in for that if need be, but for my purposes the Fire is better suited for email, web surfing, watching videos, etc. - basic tablet stuff. I'm too cheap to buy a more expensive mainstream tablet. But for my meager needs, the Fire works just fine.

Calibre is quite the excellent piece of software IMHO (shameless plug for something I really like, but I have no relation to it other than being a very happy user).