If you otherwised liked the original Revoshift shifters, then I'd order up a new pair of them. Your original ones were probably SL-RS25 or SL-RS35...which are on the lower end of the Revoshift line. I recommend the SL-RS45 or SL-RS47...whatever you can find easily. These, with the silver bodies, have a much nicer shift feel than the lower grade ones. Pulling cable feels about the same between the two, but letting cable out is much nicer on the higher grade ones. The low grade ones just have a harsh snap-snap-snap feel, but the higher grade ones have some sort of clutch or slip mechanism inside to where you apply twist force and the cable is released somewhat slowly to where it's not just a snap/bang. It's not a 1:1 movement.
Hard to describe, but easy to appreciate, if you've felt the difference between the two.