I used sparknotes only when i coulnd't find the resources elsewhere. Their information wasn't always organized well, written well, and the content wasn't always the best, occasionally informaiton was even wrong.
Back when i needed to get through English, without ever reading, i primarily used
www.pinkmonkey.com and used their booknotes. Most of the time i could get everything i needed to off of there. If i couldn't, or if some sections weren't clear enough, sparknotes makes a good supplement or back-up source.