You are thinking about this all wrong.
People are under the impression that Sportbikes are all the same except 250s are for beginners 600s are intermediate and 1000s are for experts. Theres much more too it than that.
Motorcycles are highly specialized tools. A shotgun is for fouling, a .270 for deer hunting, a .45 for defense etc. There are no beginner guns, though there are user friendly ones. Bikes are the same way.
You are looking into R6, 600RR GXS-R, ZX-6R etc right? They are highly focused track tools. You want a fun transportation device. Thats like using an uzi to hunt deer.
Without knowing your proficiency, intended use or budget its hard to make a suggestion.
Look into The Suzuki GS500F and GSX650F.
They are stylish, pretty entertaining, comfortable and frugal.