I'm not a rabid campaigner for Mobipocket, but it definitely has the advantage over MS Reader of allowing for the downloading of secure books directly to the device without going through the PC. At least on one of the book sites, MS Reader is disabled for auto readback of secure books. Mobipocket is smaller (1.6 compared to 2.3 mb). And Mobipocket is used extensively on fictionwise and ebooks.com, the two places where I get most of my books. (Mobipocket seems to be the "recommended" reader on Fictionwise.) However, all of that being said, I won't be terribly disappointed if MS Reader gets the green light ...
Here's the link to the manual install download site for Mobipocket (something else you cannot do with MS Reader; that is, install the reader without a PC!):
http://www.mobipocket.com/en/Downloa...ualInstall.asp
Thanks,
jendand