I don’t normally use Google TV, but I thought it was tied together with several other platforms and share many, but not all, of your purchases between the various services. I’ve been using Fandango at Home, formerly Vudu. Some years back Movies Anywhere hit the scene and looked to be entering that same space. I’ve also noticed that Amazon and Microsoft use basically the same library. I believe when there is a difference, missing content, it is usually because a movie studio is not affiliated with that service. So, Fandango is where I have my complete library, but I can find like 80% of it on a handful of other services as well (linked).