I've had both a Freeze & Superego, and I sold the Freeze as I prefer having more control and the connection options that the Superego has. Both do the job regardless, but I guess it depends on budget, board space and if you want the ease or more control of the overall effect.
Food for thought; If you like the sounds of the POG series, then check out the HOG2, as that does both POG & Freeze effects in one box.