Ok, seeing as people are still stuck on using random sourcebook blanket statements in debates instead of in-story evidence, hopefully this should end it:
Dave111283 (Darth Sexy): Being a huge Marka Ragnos fan, I just wanted to know where he ranks among the most powerful sith lords ever. The way he was always described made me think that he was the most powerful Sith Lord ever until sources came up with Sidious being the most powerful. Can you shed some light on this please?
Captain Yossarian (random dude): I don't know for sure but I would imagine that there are no hard and fast lists about which Sith are the most powerful. "Most Powerful" would have lots of different variables to take into account. So it may be best to say that he was simply amongst the most powerful Sith along with Sidious and whoever else there may be. It you definitively say that one Sith was the most powerful then by definition any others that you create in the EU must be inferior so I doubt the continuity people make such absolutes about the powerfulness of the characters. Of course, I could be wrong though.
Tasty Taste (Leland Chan, the guy who runs canon): Agreed, us continuity people don't deal in absolutes. Only Sith deal in absolutes.
With that said, we'll often need to come up with stats or rankings for gameplay purposes. These are for gameplay purposes only. Stunt coordinato Nick Gillard had his own lightsaber ranking, but even the use of this ranking system is limited because it was only the major characters from the prequel films that he ranked. We never expanded on that ranking system.
So as you can see, the head of the canon department himself states that these random statements aren't absolute, and thus, not a deciding factor in these debates.
Here's the link: http://forums.starwars.com/thread.jspa?threadID=152583&start=1200
Now can we please stop all this relying on blanket out of universe statements, and try and use in-story evidence from now on, as you can all quite clearly see that Leland Chan has basically confirmed that they don't mean jack, except for gameplay purposes.