Very good question.
In the IS-F it was a case of 'Look - somebody is looking at the car'. In the RC-F it's a case of 'Ooooo, that person isn't looking at the car'.
I think mainly good attention. Kids will video the car, people will slow down on the motorway and on the rare occasion that I park up in a busy place, people will engage in conversation about the car.
I suspect that a lot of the looks are along the lines of 'What is that!?' - in a positive way!
Boxster is a great car. Like my RC-F my Boxster was a second car, so it was a special occasion every time I drove it.
The engine in the Boxster was great - especially when it came on song and made that special noise (which I can't describe).
F cars are totally different beasts to a Boxster. The V8 is central to the package. You'll get refinement and performance in one package. You'll also get utterly ridiculous reliability - no RMS or bore scoring issues. Stuff like that is unheard of.
In the RC-F the car will get the recognition that ALL F cars deserve.
Finally, you won't see many on the roads!