The LA Times has more details on this ereader which, they say, will be released this fall. The article says that the display can last from 18% to five times longer than an e-ink display, depending on thow they are used. With a mix of book and magazine reading and some web browsing the e-ink display lasted 7.3 days compared with Mirasol’s 8.6 days.
A slashgear article gives more details.
http://www.slashgear.com/qualcomm-mirasol-e-reader-coming-fall-2010-1574081/
In particular, it mentions the number of pixels in the display – 1024×768. A 5.7″ screen at 1024×768 is about 225ppi. That’s a lot better than the 166ppi of the current 6″ eInk screens.
No info on how fragile there are though.