Prime is without a doubt the best value I think, you're getting the Amazon site perks, Music, Prime Video, and they recently added some sort of access to read comics online which looks kind of cool but I haven't dug in yet really.
Never heard of this before but now I have to skip past an ad for it every time I put in a classic Doctor Who bluray lol. I like the tourism ad they made for some of those blurays that has Tom Baker narrating what is essentially a travel agency ad for various Doctor Who locales. Weird.