Became frustrated trying to get a sweep NOT to create a miter at a 90° corner and instead create a 90° arc that would be a quarter radius where the inside of the radius is the inside corner of the change in direction. (see attached). It won't work for a Chamfered corner either, where the Chamfer is 0 on the inside corner.
It would be nice and easy if there was a "toggle" or check box to choose between "Miter" "Chamfer" or "Radius".
The only way I could find to accomplish this was to create the initial Sweep with the unwanted miter, then create a void and remove the unwanted miter, then create a sweep of 90° in the spot you want it. The only problem with this is that the little fillet corner will not join to the original sweep. So annoying.