Kreia says a ton of shit, but given it doesn't reflect the actual Sith, only Avellone's non-existent concepts of the Sith, it doesn't really mean much besides hyperbole.
At best we can say Tulak Hord is probably better than everyone in Kreia's day. Then we have the fact Exar Kun got all his special skillzzz from a holocron containing 100,000 years worth of Sith knowledge. Presumably why he can bulldoze every other duelist of his era.