I didn't know about Feather 3D, but it looks super aesthetically pleasing. I'll have to try it out.
I tried uMake a while back, but found the 3D viewport navigation a bit hard to use, and would often find out I had been drawing on the wrong plane after orbiting the camera.
After using something like Tilt Brush in VR, it's hard to go back to a 2D screen that doesn't instantly communicate the 3D location of the brush strokes you're placing.