What do you mean by differences?
I got Mountune today and you get no intrusion from the kit in the cabin, sounds almost stock but when the windows are down you can hear the recirc valve very clearly. The Mountune air filter is a k&n panel in a redesigned lower air box with a 2nd cold air feed, looks almost stock tbh.
But in terms of whether you can see gains from either filter, its not something you can compare as one can be bought separately and the other comes with a remap regardless.
If you want to grab peoples attention then Autospecialists is the way, but if you want a bit of subtlety then Mountune is a good option.