Digital is always better, IMO. Plus with the digital Ranco's you can set your differential based on what is ideal for the compressor that becomes it's slave.
IIRC, the Johnson has a non-adjustable default diff of +/-4*F which isn't bad for the slave compressor but is about 2*F too much than necessary for a new compressor.
I have the Dual stage and love it. If you have you'r box outside or in the garage you'd do well to consider it. But if all you need it for is a kegorator then the single stage is perfect and in-expensive.
I was able to loacte a local heating and refrigeration supply and realized a cost saving not just on the principle but also no shipping and no waiting. Had to wire it myself tho' which was a bit daunting as I know just enough to burn the house down. I had an electrician friend check my work before I plugged it into the grid and all was chill.:fro: