In my opinion..
- moves >> IVs
- It depends on the pokemon; generally, a pokemon benefits from having IVs in stats which are it's weakest, compared to its other stats; it's relative.
Example: Cloyster has amazing defense but mediocre attack and poor stamina/hp. In this case, it would be ideal for Cloyster to have higher attack and defense values.
Cloyster's stats (atk/def/sta): 186/323/100.
I BELIEVE* the way IVs work is that when a pokemon is maxed out (i.e. cloyster), it will have those stats PLUS it's IV values.
So in this example, a cloyster would benefit more from having stamina IV's compared to defense IV's, as 323 def / 115 sta is more ideal than 338 def / 100 sta.
Another example: I have a chansey with (atk/def/sta): 15/15/6. I chose to evolve it because it was already a high level upon catching it (less candies) and a lack of hp IV's wont make a significant difference as it has perfect attack and defense.
(https://pokemongo.gamepress.gg/pokemon/91)