I've been reading ebooks on several versions of Palms, for 10 or more years. My current Palm is the Tungsten T3, which you listed as one of your choices. It's great! The screen expands to give a longer page before you have to "turn". I set up my "ereader.com" software so I just tap at the bottom of the page to move downward in the book. You can also set it up for left/right clicks if that works better for your brain. Then again, that is specific to the ereader.com software (which is free). It works on text files as well as their book format.
You can also put a mobireader on the T3.
In short -- I highly recommend the Tungsten T3 if you want to try reading on a pda. I got my Kindle cuz my eyes were beginning to object to the backlit format, but that's an age thing. I loved pulling a pda from a pocket, to read a book while waiting in the grocery line!