Jerico is spot on. Overall speed is not noticeable I don't think so on the face of it, it is only the fact that it will hardware decode H.265 encoded videos or channels. As we don't have any channels encoded in it, it leaves you with videos and I haven't see any as standard yet.
If you want a faster box you would be better looking at something with a faster CPU, something like the Edision os Mega at £179. Works exactly the same way, but will feel a lot faster through the menus etc. Then the list goes on and on and on with numerous boxes at costs increasing.