apss for iOS are better optimised than for Android. That's one reason for such faster load times and the other reason os the faster storage.
Other than games both of them are same.
The one plus 3 is even faster than the iPhone7 for normal tasks.
I don't think software optimization done wrong the A10 fusion chip is 3x faster and that makes game launch faster this means only a better processor needs to beat iPhone 7 but till that it would be the fastest phone.
So for all the much touted performance of the iPhone 7 it doesn't show up at all in usage, other than for loading games (which may be because of storage speed and not the CPU/GPU).
Performance really is looking to be a non-issue.