GooReader was just announced this morning, and it made a splash this morning in the press. FYI: it's a reading app for Windows that ties in to GB (Google Books). You can search GB and read the books from inside the app. There's both a free and a paid version ($30).
The paid version is the first reason why I recommend everyone avoid this app. The only feature it adds is the ability to download PDFs. Google will let you do this in a browser, and it pisses me of that GooReader wants to charge for the privilege. BTW, Google will also let you download Epub, which is something GooReader can't do.
I've tried GooReader, and I compared it to using Google Books in a browser and Adobe Reader.
First, GooReader doesn't have any real library abilities, which I'd have thought was the main reason to install the app. All it can do is search GB (much like you would in a browser) and then display the books found. Curiously enough, GB has some library functions. I haven't used them so I can't comment.
When reading the book, GooReader is slower than reading the same book in a browser. It was also slower than reading the PDF. There is one small upside: GooReader lets me use more screen real estate than when I use GB in a browser. I don't care, though, becuase if I'm going to use a book for any length of time I'll download the PDF.
GooReader has a fair number of zoom options. It also has one rather neat feature: it lets you rotate a book (so you don't have to tilt your head). I like that. But it doesn't have any annotation options (not even bookmarks), nor does it save your place in the book.
Whoops. I just managed to crash GooReader, so I'll cut the review short here.
GooReader is not worth the money to buy it or even worth the time to install it. It might be worth it in the future, just not now.