Anyone used one of these to any great degree yet?  I was thinking of getting two to run Kodi primarily on them to replace my Mediaportal setup - one will be connected to a normal tv, the other to a 4k tv.  

They would be connecting to a server running TVHeadend for the FTA freeview channels.  Everything else would be stored on the server as well. No streaming services at this stage other than maybe IPTV if I can be bothered. 

I was thinking of using one of my Rpi 3's but they dont really seem to be 100% up to the task of running some of the channels all that well - lots of artifacts on TV2 but that *could* be from the tuner Im using to test (cheap USB one with a cheap indoor aerial).  I did test on my Libreelec NUC and that didnt seem to have any issues though. 

Speed wise are they pretty reasonable?  I found the RPI's to be very slow at changing channels etc whereas my NUC was very quick.