Like all new technology like that, I'm waiting to see if it "sticks" as well as all the bugs getting worked out. I wouldn't want to jump in early and find that too few people use it for them to continue supporting it, and some other reader appears on the market that's more popular and better supported and uses some other format for reading content incompatible with anything downloaded to the kindle.
With any such reader, my biggest concern is sun glare. I like to sit outside to read on nice days, and nothing I've seen compares to a good, old-fashioned printed on paper book for readability under those conditions. The other time I often read is while flying, and if I can't have the reader on until they permit other electronic devices to be turned on, it's not really going to be available during the time I really want to be reading a book.
I could see it being nice for students though, who can carry around one small electronic reader rather than lugging around a bunch of books for classes. Not sure about studying from a reader like that, but it would be useful for some quick reading between classes, or to be able to look at a problem assigned in class without lugging the book everywhere (ideally, for textbooks, I'd want a paper and electronic version bundled...keep the paper copy home to study and as a permanent reference, and the electronic version for portability during the day). Certainly would be good for traveling when you don't want to carry a lot of books in your luggage.