really can't compare the two boxes The cloud is an enigma2 linux box and the skybox well is a skybox. The enigma boxes are a lot better, but require a lot of setting up out of the box. picture quality is the old saying the more you pay the better you get. once setup correctly then all should be good.
The skybox easy setup picture quality average and they need some updating of channel ists as channel freq move cause sky like to do that for some reason, and you would need to keep updating the EPG to keep the list alive.
Skybox good as a first box and you will learn loads about how this satellite stuff works, but if you want just watch tv, and not have to worry if the channel will be there when you switch on then a linux box. Thats just my view. Hope it helps a little.