Generally speaking 3 bladed heads tend to wind-plane less than 4 blades. Not that 4 blades don't do well. It's just that many lack the knowledge and experience to get them to fly as well a 3 bladed head. And sometimes, for whatever reason, they just get fidgety.

Then there are still somepeople who think they have to align their heads with the fletching and it's hard to align 4 blades with 3 fletches. It's not necessary, but some think so. Then there are those who do so just paying attention to every little detail.

Four blades do more cutting. That's a given, but no animal will ever be able to tell how many blades just zipped through them. Dead is dead.

Does this help?