In D3, most gear has MF and GF as an additional bonus stat, meaning it doesn't take priority on gear over a dps stat like Str or Agil, so killing speed wouldn't be effected by GF of MF on gear. Almost all talents are based off weapon dmg now, so thats one of the huge dps factors in which MF/GF would have no effect at all.
Head
Helm
103–104 Armor
+6 Random Properties
Crafted by: Blacksmith (Level 10)
Plan: Exalted Grand Sovereign Helm
Required Level: 60
Durability: 50-65
Sell Value: --
This is a crafted item, it has +6 random properties so its actually possible it could get Gold Find AND Magic Find on one item as well as Vitality, Str and so on. However the GF/MF will always be at the bottom of the stats so its also possible it wouldn't be on there at all.
https://www.deviantart.com/aerisot
Head
Helm
103–104 Armor
+6 Random Properties
Crafted by: Blacksmith (Level 10)
Plan: Exalted Grand Sovereign Helm
Required Level: 60
Durability: 50-65
Sell Value: --
This is a crafted item, it has +6 random properties so its actually possible it could get Gold Find AND Magic Find on one item as well as Vitality, Str and so on. However the GF/MF will always be at the bottom of the stats so its also possible it wouldn't be on there at all.
https://www.deviantart.com/aerisot