I have AT and would have to agree with you. It works well and it's nice to see Lambda values across the entire operating range on the display while you ride, but it definitely isn't required or even essential to getting a good tune. I transferred it from my old PCV-AT setup, but given the $300 price tag for AT if had to buy a PV from scratch I would probably go with the PV alone and tune in basic mode with the stock NB sensors, then run closed-loop.