Hamed accomplished the most at featherweight. Pac beat Morales and JMM at 130. Those are two of his top 3 wins. JMM had the stunning victories of Gainer and Medina at feather which somehow made him a top 10 p4p Barrera had some great wins- tapia, ayala, hamed, morales. Kayo loss to Pac. I would have no trouble with him being tops. He had great wins, but his reign was short. Morales had a few very good wins at the weight and lost to Barrera.
i guess it comes down to what "best" means: at featherweight- Accomplishments: 1. Hamed, 2. Barrera, 3. Morales, 4. Pac, 5. JMM Best Wins: 1. Barrera, 2. Hamed, 3. Morales, 4. Pac, 5. JMM Skills: 1. Barrera, 2. Morales hard to say