My vero4k and vero4k+ have been pretty much rock solid when it comes to playback.
Just a few nights ago I wanted to play an mp4 file ( usually I only play mkv ) while mkv always start playing just a second after starting the playback the mp4 file was loading for almost 20-30 sec and then the playback started. Fist I thought that maybe Kodi had to install some codecs or something similar in the background and that that was the reason for the long loading time ( it was the first time I played an mp4 file)
So I stopped the movie and started it again just to check and to my surprise, the loading took very long again and when the movie started there was sound but the screen stayed black.
I then again stopped the playback and started it again the loading took just as long as the previous times but the picture was back.
I than tested with other mp4 files and it always takes long for the playback to start.
If I mux the mp4 file into a mkv the problem goes away.
Before you ask: Files were played back from a USB stick formated to NTFS