Hi, I have both a 2010 catalina 6500 and a 2010 saltiga 6000gt. Apart from the ratio, you would hardly know the difference if you were blindfolded. As far as how they perform, the catalina has stopped a few 15kg+ kings and 50kg YFT with ease.
This is on 80lb braid with about 5m of mono leader. Drag is smooth on both reels and had no drama with either.
Personally I would just go the Catalina again as they are pretty much the same reel.