Not sure if "best", but I've been using sidereel.com for a while. Source: over 1 year ago

There is no app at the moment but the following website has an agreement with Vudu and it’s working on any browser https://moviesanywhere.com/welcome. Source: about 1 year ago

Didn't it just become Movies Anywhere? I bought a bunch of bluray movies recently, and they came with a code for digital (didn't pay extra, AFAIK). I entered the code into a website and now I can watch those movies online using a bunch of different services. Also, when I went and looked in my digital movie library, it contains the couple of movies that I had via Ultraviolet, so I think they just transferred over. Source: about 1 year ago

You might be able to use Movies Anywhere to get a movie on both platforms if you purchase it only on one, but that only works on movies, not TV shows. And I think only certain movies. Source: about 1 year ago

Movies Anywhere is a free, legal way to watch movies bought on multiple platforms including Apple. I wonder if there’s a way to use that service on Linux (web?). I haven’t tried personally just wanted to throw it out there. Source: about 1 year ago

If you connect your digital media accounts like prime video, ITunes, Microsoft Movies, YouTube Movies, and Vudu to the Movies Anywhere service you can access certain movies on all platforms https://moviesanywhere.com/welcome It can be really useful for not rebuying certain movies. Unless you love Vudu and don’t want to have movies elsewhere this is a good deal. It just will only be on prime unless they agree to... Source: over 1 year ago