Crowded for obvious reasons (located in the downtown area). Chairs will give you back pain. There are 'study rooms' on the second floor that fit in up to 4 people incl. (no booking though) 1 hour only
Books galore. After you check out a book, go to the park behind the library and enjoy the day. Support them by buying from the Friends of the Mountain View LibraryBook Sale every month!
You can use one of the card storage apps to store your library card so you don't have to keep the card in your wallet. The app replicates the bar code and you scan your phone during check out.