I believe it is currently out on both as well. I am using it on Android.
Using the Primarchs is actually kind of cool. So far I think they have Angron and Mortarion, and they each have a special card that takes up space in your hand for the entire game, but can be used once certain conditions are met.
The game maxes out at 10 resources to play a card, and they both start at a cost of 20. Angron's drops to 0 cost when he is reduced to one wound remaining, then he gets +1 attack (bringing him to 4 if you have no other bonuses) and +10 wounds, while also gaining the ability to attack twice. Mortarion takes more planning, though, as his ability reduces in cost every time a troop unit is killed by poison. The Death Guard do have many different ways to cause poison, so it is definitely something to build your deck around.