@pierpat: I have a couple of points to make about that:
Just because something has only been said or happened once, opposed to multiple times, doesn't make it any less credible a source. That kind of logic bites you in the ass when you're trying to use a feat/statement that is isolated, as you'll probably find out.
Here's the thing with Vitiate: this Bane quote does indeed pre-date Vitiate's own accolades, as well as Vitiate's existence. So Vitiate is probably better than Bane because he has his own accolades. That said, I still need to determine if the source of those accolades are in or out of universe. They come from the TOR Encyclopedia, which people argue is era-dependant, written within the context of the TOR era alone. But regardless of that, Bane's quote still applies to every Sith who isn't Vitiate. They don't suddenly become superior to him because one new character is. It simply relegates Bane below Vitiate.
I've spoken at length about why your personal interpretation of a feat is an inferior means of analysis than taking a factual statement and applying it's meaning, but I also respect that the majority of people are going to use feats. I personally don't think feats are useless, just unreliable, so I'm doing something different.
Let's be clear, feats can be unreliable but he're we're talking about a huge bundle of feats against one false statement.
Vitiate existing does not make the statement partial, it outright makes it wrong and un-usable to me. Because, if the statement uses an absolute and that absloute is not correct (as in bane was not the strongest) how can we know that even a small part was real? Even one discrepancy can bring down a point, and that statement is false.
So, to me at least, that statement being wrong in no way applies to every sith who is not Vitiate.