benthamite, have you had success using decks you have not built yourself?

Yes, both to learn new material and to retain material I had previously learnt. From the list above, examples of the first type include Get Motivated, List of Cognitive Biases and Fallacies, 100 Greatest Paintings of All Time, and The Major Mnemonic Memory System, while examples of the second type include Richard Wiseman's 59 Seconds, How to Formulate Knowledge and Marshall Rosenberg's Nonviolent Communication.