That is a tough question. Disney+ puts their material up very quickly, pretty much as soon as the DVD is released, so if their content (and they have a lot) meets your needs I would say they are the fastest and they have a large library. Netflix has a lot of original content, so you can get brand new movies there which is especially important with theaters closed. They are hit and miss, but they also don't have to be blockbusters so Netflix takes more risks and plays with the format. For example, "Queen's Gambit" is one of the top things I've seen this year but it is essentially a seven hour long movie (told in seven one-hour bites).