EDIT after a week of vacation and test:
So, now, the device that acts as a large tablet, I created a google play account, I downloaded the xbmc Kodi, the box not react at all bad, it is enough fluid in the android menus, the use of youtube is correct, I even tested the streaming video, correct too, same with Miracast, who also works.
Let's get to what is going less well in my case, and why I have decided today to redirect this box:
Once installed and configured kodi (there are plenty of tutorials on the web so it's relatively easy to find sy) you can enjoy your media libraries, but here, at home, I noticed that the xbmc kodi, tended rowing, you know, when in the navigation of the menus, you have trouble selecting something, well that I can not stand! I thought, ok, may be that there is too little, it is true that I have some coupled NAS ... but know that with xbmc kodi, you can add a multitude of addons and for me, I have not added 5 ...
For videos in SD, my time, it's still reasonable, it lag a bit before starting the file at the beginning and then it's ok, everything is fine, no lag during viewing, by cons, when it ask to read a video in HD and again, I was nice, I had him read a file 3 gigas, and well, the picture stutters all the time! Before coming to writing this review, I heard my WD HD Live reconnect, which itself able to read this file 3 gigas and even another 19 gigas originating from that NAS. So my setup nothing to do.
In conclusion, I would not say it is a bad product, especially for the price, but for me, this one was not up to what I expected.
I hope my comments will serve to others.