Overture: I own infuse 4 pro since end of June 2016. Because I was frustrated by the update policy to version 5 (I downloaded the free version and don't feel compelled to upgrade), I was looking for alternatives.
I ran across Squire player and bought the Apple TV version for 4 Swiss Francs (approx. 4$ or 4€)
Since I have PLEX running on my Synology DS415+, squire needed no helper app to run on a Mac.
I started the app on my ATV4, movies and Shows on PLEX library on my NAS were discovered and appeared immediately on Squire and I was ready to go! Nothing to set-up except registering an account for cloud service to sync your library across the different devices (Mac, iOS, tvOS).
The UI is beautiful, clean, including Trailer and Search. Features like Watch Later, cast and similar are also nice but not more, for me.
I played few large mkv files (Ex-Machina, 2012, etc.) and it works very good (smooth video, excellent video/audio sync, subtitles on the spot too!)
Can really recommend it if you have a Plex server running somewhere.
BTW: Beside infuse 4 pro and Squire, I also have Kodi 17 Beta7 (side-loaded), VLC and PlayerXtreme. I find Squire the best until now.