The unit that’s best is the one you want to be in. If you know for a fact, you don’t want a high number of patients (walkie talkies) then PCU is your best bet.
Med Surg is good for time management skills but you can definitely learn that in PCU. PCU is good too because you can do MS/Tele or Stepdown or cross train to the ICU or ER. It’s fast paced with high acuities and turnovers.
Med-Surg is also good if you want to see beginning to end pathophysiology since a lot of those patients are frequent visitors with chronic illnesses.
Discard the idea that med-surg is mandatory for skill development. If you know what you want to do, go for it.