I think it is the EarMax Pro. It sounds exactly what tubes give to it, slow and tuneful sounding. I guess PPX3 just provides more energy to the headphone, so it should be faster and more accurate. It really depends on what musics you prefer the most usually. I am always enjoying EarMax Pro on all the vocals presented. It sounds like magic, very musical and emotional. I spend lost of time on the EarMax Pro. I compared it with GS1 and Black Cube. I still prefer EarMax Pro for the vocals. If you like classical music the most, you may not like the EarMax Pro.