I had one and did not care for the ergonomics. The linkages make things slow going, and the throw is really long. Very high quality press thatvisbtypical of Redding. I never did have a need for the leverage that it afforded since my Rock Chucker(s) could cover everything that I needed a SS to do. No way I would recommend a UM as a sole SS press unless case forming was a regular ordeal.
I have has 6 single stage press, and the current RC is the one I prefer.