Chandler-Sunset is awesome. It's clean and well organized, and the staff is amazing. They are patient and kind, and always make time for you.
The library isn't huge--if you want big, go to the Downtown branch. However, they're always happy to reserve things on hold and have them delivered to Sunset for you. They have study rooms and tables to write or work at, as well as computer stations.
I love the self-checkout system they have set up. It's awesome.
If you want a great place to go and work, read, or browse--forget B&N, go to the library.