I only ever put V Power in mine. However it's easy for me as there are stations on my daily commute. I think it would be a different story if there were no Shell's close to me. In such case I would buy the highest RON available on my route.
The issue with Nitro you have to remember is that they will have changed it long before the promotion and launch of Nitro began. So in a blind test I doubt any existing V Power user would see or feel any difference in the upgraded version.
The question is, how does it compare with competitors Super fuels. It's just too hard to do a real comparison as there are way too many variable that can affect the results of such a test.
Yep. The fuel was rolled out a while ago. They've just been changing the pump labels over gradually
Can't say I've noticed a difference tbh. Any slight difference detected will be because of the friction reducers. It's the usual drip fed marketing and don't forget Ferrari and Shell are in bed with each other, so there's a subliminal message there: Ferrari = sporty and fast, so must be good fuel. 3 years on from now they'll launch 100 RON (which has been in Europe for years already) and 15% more friction modifiers.
As for competitors fuels, I like BP Ultimate as it's consistent. Tesco Momentum & V Power seem to give inconsistent results. Esso's 98 Ron is OK too. And before anyone says BP is only 97 RON, data log your knock channels and you will see you get knock on a standard R32 even with 99 RON
Morrisons E85, hmmm, now you're talking
108 RON IIRC. Used it on my VR6 Turbo and the motor runs so cool, you don't need knock sensors or even an intercooler with modest boost levels.