Had much fun playing this deck and it actually works on the ladder very well. Pretty bad against some archetypes just as the new Big-Green-Landramp, Blue-Green-Beast and anything that runs Frog-Tossers. But its working against Red-Control, Red-Yellow-Burn, Blue-Jump/Triton, Green-Yellow-Sacrifice. Even Yellow-Mistral-Rush decks or very aggressiv Scourges of the Oversky have been beaten by this.
Its very viable to play. You can just start by building a lot of cheap creatures in front of your Orb and then go for big Salamanders to gain insane value from Revellers and Long-Horned Yaks (Also amazing in combination if you draw like a 9/2 Reveller after a Yak has died) and just outvalue your opponent. You can also build to one side if it seems to make sense to block your opponent from double collecting or early aggression. But also if you play more defensive, you can start putting pressure on your opponent pretty fast if you find the right moment. Cards like Garudan, Majinata, Yakkapult, Salamander and even a late game Mother of Yaks can swing the game in your favor. Ruby Yak also is a solid win condition in this lineup.
It would be nice to see some more Yaks on the ladder and not only in casual games. (AniMatE614 is playing an amazing Deck there with Mistral Guides and Saphire Yaks that this build can't do anything against)
I really recommend to give it a try ;)