[hn8305823]

Also, the use case for quaternions depends on how many times you will be applying the same rotation. If it's a few or dozens of times then maybe not the most efficient. If it's million or billions then you are going to want to use quaternions.

This is mainly due to the cost of converting to and from the rotation vector.

[xeonmc]

i.e. keep it in vector form if you're combining them a lot, convert to polar form when you want to work with angles