Best you look at it carefully. The gist of COS 08 is that you will take a lot longer to advance due to higher retirement ages/ direct entry FO's and soon to come reduction in crewing levels on long haul flights.
All these will slow down your career substantially. On COS 08 you will get ZERO compensation for this. If you are younger than 25 - fine. If you are older than 30 - think carefully.