tbh Vader destroys him. Post Mustafar Vader's potential is still somewhat comparable to Sidious's, and by 40 he's likely realized enough of it to far, far, far outstrip what Scourge's is, which is infinitely lesser than Vitiate's, for instance. Likewise his feats demonstrating his raw power are drastically superior thanks to The Force Unleashed.
Scourge won't get any compensation in saber skill, since Vader has been noted both as himself and as Anakin to be one of the most skilled bladesmen in all of history, besting various potential contenders for the most technically skilled duelists of all time, most notably Dooku. Upon getting into his suit, he created a form incorporating multiple traditional styles within a matter of weeks. As a padawan he was able to challenge and impress Dooku himself. What has Scourge done? He's good at Juyo and can intimidate some dark council members, ooohhhh.