I have an older PocketPC (
HP Jornada 540). For me, it's primary use is for reading ebooks. I also use it for IRC chat, playing puzzle games, & very basic web surfing during hot summer months. (There is only 1 room in my home with air conditioning, and my desktop computer is
not in that room.)
I have both MS Reader and Pocket Adobe Reader on it, so I can read both .lit and PDF.
I prefer .lit for a few reasons, but the primary reason is file size.
There is an issue with certain PDF files, mainly related to either the age of the file or the software that was used to create it.
Pocket Adobe Reader reformats the files for reading on hand-held devices. To do this, it relies on a
tagging system that is embedded in the original file. When you transfer the files from your desktop PC to your device, they are converted. With newer files containing real text, created in Adobe's own pdf creation software, there really aren't too many issues and it works pretty well most of the time.
The problem is really with older files that don't have these special embedded tags, and files created with certain non-Adobe pdf creation software that doesn't add them...and those files that are actually images and no real text can't be converted at all, to anything readable on my handheld device.
When you attempt to transfer a non-tagged, text based pdf file, from your desktop pc to the device (through ActiveSync), the automatic conversion utility will try to add tags to it (by guesswork) and the end result is a file twice the size as when you started (it also isn't always correctly tagged). PDF files are usually much larger than .lit to begin with, and when it's finished converting you could end up with a pdf book that takes up the same amount of space it would have if it were 25-30 copies of the same book in .lit format.
When you only have a 250mb CF card for storage, that can be a real issue to consider.
And I will agree with everyone else about handheld devices being good for reading novels, but not so good for reference books in which you would need to perform searches for info. MS Reader does allow you to create bookmarks, highlight passages, and write page notes (text & color doodles), much the same way you could in a physical book, but you would still have to do that first in order to find something again later. A dictionary in .lit is pretty much useless. As a matter of fact, a dictionary in pdf is also pretty useless on a PocketPC.