The Phase Vibe in the KPA does an ok job, if you know how to set it up. It's just missing some of the wobble that the Uni/Rotovibe had (the model in the Helix is the best digital emulation I've heard).
The kemper rotary has only two fixed speeds (fast or slow). This is a small limit. Maybe there is a way to change and customize the rate, but I do not know it.