My group adopted this method a few years ago and have never looked back. It is a much easier and faster initiative system than anything else I've seen, and a quick reshuffle of the cards means we can switch it up every round with zero bookkeeping. It worked so well that I went out and bought about 5 or 6 of those face cards from Paizo and we use them for PCs, monsters, NPCs, etc. Some of my players have had a few gripes about not knowing the order of initiative, but we all agree that the ease of use is worth the trade off.Once I used an initiative variant where each PC and NPC had their names written on blank playing cards. Then during combat the cards where shuffled and play went in order the cards were drawn. It was quick, easy, and I loved it. However the players hated not knowing the order ahead of time.