My bank rewarded me with a PSP a year ago and it's now my main ebook reader (having moved up from mobile phones and PDAs). I've got an MS Word macro set up for the PSP's screen size that does all the formatting hard work, then I print to PDF. I'm using Bookr v8.1, which opens txt, pdf, djvu, fb2, and rtf files.
I've found that it's easier on the eyes if I use a black background and light grey fonts. Battery life is fairly good as you can set the CPU speed from within the program, and all the buttons are customizable.
Reading in direct sunlight is completely out of the question, but on the other hand I can read at night with the lights off and not bother my better half
