Aren't they the longest established intext ad company? Whatever, they seem to have the best inventory of GOOD advertisers that they deal direct with - that's why we went with them.
The only downside is the level of traffci you need to get a deal... :(
We've seen up to $0.60 (our share) per clickthrough on their premium partner campaigns. It does take some clicks from Adsense - but in our experience only about 10% loss .... whilst adding another good rev source.
I can't comment on Kontera - but when I researched I saw a lot of sites that with Kontera they were showing backfill results from Y! (I think) - which means low CPC rev rates as you are getting a % of a % plus, and even with Y! they simply don't have the level of advertisers to fufil a lot of smaller keyword terms.
If you are a financial site - then this will be a very good rev source I think.
TW