Moveset is more important.
Since it's unlikely you'll have to decide between a 100% and 0% Pokémon, the difference in CP will unlikely be 10%. Considering many moves have drastically varying DPS output, that's what you'd want to focus on.
Then again, it looks like Niantic is actively rebalancing things, so everything is subject to change.
Exactly. And just to clarify for everyone because I think Jae had a typo...
Jae means that most of the time when you're comparing IV's it's not a 0% to 100% perfection rating. So most of the time you may only be seeing a 5% uptick by selecting a better IV pokemon. That's compared to getting a Water attack like Hydro Pump...