Parasound P/PH 100 verses NAD pp2 or Rotel RQ 970

The lack of replies may be due to no one having these exact phono stages to give you a meaningful answer.  Also, since they are all discontinued, we do not know why you want to know.  So time to rephrase the question.

Do you currently have them and simply want an opinion on which to use?  If so, your in the best position to tell us.

If not, are you considering getting one of the three as a used purchase?

If the latter, then tell us what cartridge you have and we will be in a better position to assist because even without having one, specs would tell us which will match up better with your cartridge.