I'm building myself a new bike from part second hand, part new components. In fact I now have all apart from the groupset which I intend to buy new.
It'll be Campagnolo for ergonomics preferences... Helped by my 3x9 Mirage setup being incredibly durable when compared to my 3x9 SLX. I do realise it'll cost more than 105
It'll also have to be 34x32, I use the 30x28 wimp gear on the Mirage bike too much to give up on such low gearing!
I can find Centaur 2018 / 11 speed from £450 in Germany.
Potenza closer to £650... (including BB30 bracket cups) Maybe slightly less if sourced from several shops and using the older powertorque crankset many shops are trying to dump. (2018 Potenza is now also ultratorque)
Ultratorque does seems easier to service, even when compared with the self extracting version of powertorque used by older Potenza.
Is Potenza worth the quite a bit higher price? Mainly from "pleasure/ease/fun to use" point of view, as I'm unlikely to race.