I think Luke’s potential is higher obviously since George stated he has the same potential as his father. Tho with a saber even episode 1 obi wan was amazing. Luke didn’t have much training with a saber in comparison. But at his peak was probably obi wan ep 1 or maybe 2
Honestly, at their primes I'd give Vader wisdom and both experiences. Vader at his prome has been through so many battles and learned through all of his mistakes as Anakain.