Here's the answer - Mr. Robot LOVES math and the numbers don't lie. I used a Marksman hunter with the raiding setting and the arcane shot build. But the math can be done for any set of stat weights, for any hunter

- Agility: 3.72
- Hit: 3.74
- Crit: 1.66
- Haste: 1.61
- Mastery: 1.38
- Attack Power: 1.19
So here are the comparisons:
Seal of Primordial Shadow:- 286 Agility * 3.72 = 1,063.92
- 459 Stamina * 0 = 0
- 184 Exp * 0 = 0
- 200 Mastery * 1.38 = 276
- +73 Hit from reforge * 3.49 = 254.77
- +50 Agility from gem * 3.72 = 186
- +10 Agility from socket bonus * 3.72 = 37.2
- Total Score: 1,816.97
Emergency Descent Loop- 251 Agility * 3.72 = 933.72
- 459 Stamina * 0 = 0
- 184 Haste * 1.61 = 296.24
- 148 Mastery * 1.38 = 204.24
- -73 Haste from reforge * 1.61 = -117.53
- +73 Hit from reforge * 3.49 = 254.77
- +50 Agility from gem * 3.72 = 186
- no socket bonus
- Total Score: 1,754.44
Virilian Signet of the Avenger- 236 Agility * 3.72 = 887.92
- 459 Stamina * 0 = 0
- 181 Haste * 1.61 = 291.41
- 134 Mastery * 1.38 = 184.92
- -72 Haste from reforge * 1.61 = -115.92
- +72 Hit from reforge * 3.49 = 251.28
- +50 Agility from gem * 3.72 = 186
- +10 Agility from socket * 3.72 = 37.2
- Total Score: 1,722.81