Quaternion is kind of defining rotation axis by it's XYZ components / divided by sin(angle/2), so it's seems to be very similar to Axis+Angle in that sense.
Though when we interpolate between axis+angle it's straight forward interpolation from one axis0 to axis1, from angle0 to angle1. But when we linearly interpolate between quaternions, we interpolate between angles and axes too but they are kind of mixed together, so it probably produce somehow different result.
I've found that quaternion rotation interpolation seems to slow down visually when rotation angle goes to 180 degrees. But quaternion allows to implement slerp (spherical linear interpolation). I've found some great visual example on this that captures it perfectly. Any similar issues with Axis+Angle or other issues with quaternions?
My question is what are the differences between axis+angle vs quaternion interpolation? Perhaps how can I see those differences visually to understand when one is better than another in terms of animating object's rotation.
PS performance and resource issues are not important in this matter