I find it really weird how people notice a night and day difference with fuels. I put BP 102 in my car a few months back for a day at the drag strip, and to be honest, if there was any difference, it was absolutely minimal and certainly not noticeable.
Every car I have owned, I have never noticed any difference with different fuels, although I do run my car on V-Power all the time just as I did with the last one, but Sainsburys/Tescos fuel seems to be as good.
I never use BP Ultimate as it is way over priced and has lower RON than other fuels.