There are many options for using M3U playlists, but I thought a list of apps that I have experience with might benefit somebody..
Some apps I recommend for using M3U Playlists are as follows..
The VLC Media Player works for almost any machine (including Android, Windows, and Apple devices), but I don't think it includes Electronic Program Guide (EPG) capabilities. I recommend this app for every device, as it plays nearly any type of video that you throw at it.
A Private Media Server may be the option you're looking for, but it requires some setup (and may cost a pretty penny depending on which option you choose).. Plex, for example, is one of the only M3U players available for Roku devices!
IPTV Extreme or IPTV Extreme Pro is one of my favorite M3U apps for my android phone. The only difference I can see between the two is that the pro version gets rid of the ads banner. EPG is an option with this app, but I never use it myself (I only watch two channels anyways).
Perfect Player is one of the first apps I used with M3U playlists, and it works great! The only issue I had with it was that it did not like links with the "https", but rather preferred the "http". The EPG works with this app, and it has a great background play option that I use with my android box (this way I can have YoWindow screensaver playing with music).
TiviMate is a great program for Android TV devices, and the EPG works quite well, but it does have a subscription fee for anybody that wants to use the premium features (You can download a pirated premium version of TiviMate HERE).
TV IRL is an app that works well on the MiBox. It integrates the M3U channels right into the native "Live Channels" app. Install this app, add your M3U playlist, then update your Live Channels app to see all your M3U content along side your PlutoTV & other sources in one app!