Another one I recomend is MrMC, which is a Kodi clone for the Apple TV, that is available in the Appstore.
You can set up Simple Client PVR in MrMC for using your m3u remotely or locally and also setup your EPG source for your IPTV channels.
There is no point in what is best. Everyone has different opinions and needs. Therefore, I recommend you to test as many iptv applications as possible until you have found one you like. There are many of them in Apple and the Android Market!
Don't lock yourselves to gse and iptv smartest. they have begun to become very unstable as there are very many who use the applaions and the provider has not dimensioned the server to so many users!