Stremio is hard to beat for ease of use, but personally I prefer Kodi/Fen for

1. Kodi's ability to customize audio - ie turn up center channel so you can actually hear what actors are mumbling without needing to constantly adjust the volume
2. Fen's interface and ability for the user to discover new content

The downsides are Kodi's (relative) lack of stability compared to alternatives and the fact that you have to manage storage meticulously if you're using a smart device to run it. Kodi's thumbnail cache can get out of control rapidly.