If I'm navigating (using a mouse and keyboard, not a 3d space mouse), outside of a sketch it works Almost as expected. Oddly, I have to actually select a point first. With surfaces/solids I just hover, middle click and pause briefly and it rotates around that point in space.
So see the video there, I have to left click first, then middle click to rotate. But that doesn't work once I'm editing a sketch.
Am I missing a setting? This makes editing 3D sketches quite difficult.