I'm running Castrol fully-synthetic racing 4T (something like that, it's in a green bottle) oil in my bike. Bike runs fine, fuel consumption is down 25% and gear shifting feels lighter, smoother, hasn't jumped out of gear since using it and there is less crash bash grind going on. Though not sure how much of this might be related to the bike wearing in and settling down, but there was an instant improvement after switching from semi-synthetic oil.
As for your question regarding the CBR600RR. There is a guy I know who rode such a bike and simply used the $10/l mineral oil in his. Remember asking why and he said it was perfectly fine for it and never had any worries with his previous bikes. As for long term suitability et al, sorry, have no idea because this bike got totalled in a crash vs a cage within 12 months.
Hope that helps.
90% of the time spent writing this post was spent thinking of something witty to say. It may have been wasted.
Bookmarks