Openelec is a Linux OS that runs on the Raspberry pi that has TVMC/Kodi built into it.  Upon install it has none of the repositories you need to watch movies.  You have to manually enter those.  There's a zip file I have with the top repositories(at that time) and I use that. To be honest..Genesis, Phoenix, Icefilms, Sportsdevil are all you really need.  Unless you're into International, Anime or things like that. On Sunday's, I have access to ALL the football games. Even all the PPV events.    
    
Yes.  I did have it using wireless with a USB stick I put in the 3rd USB spot, but it would be choppy at times.  Needed to buffer. It was annoying, so I ran a cable directly from the Raspberry pi to my router.  Works great now.  
Since I started this, I shutdown my 2TB Plex server. No need to deal with torrents and store locally when any and everything I want to watch is in Kodi.    
I even have it running on my Mac.  I use this when out or in my bedroom at times instead of the firestick.  They tend to be choppy as well.  I run ethernet to Mac and HDMI to TV.  Works great.     
What it looks like 
http://img.photobucket.com/albums/v640/CLovaR1/IMG_20160113_103639_zpsdgztacir.jpg