Have had 3 MINIs. All have come with run flats. And I believe all were Pirelli brand.
All 3 cars felt ok though the tires were not as grippy as those (high performance) tires on my previous cars, a Boxster and a 996 Turbo. But the run flats offered a degree of peace of mind that I didn't have with the high performance tires and their propensity for collecting punctures.
Maybe high performance tires or just non run tires would have delivered a better experience -- well provided they avoided a puncture -- but neither of my MINIs felt like it was handicapped to any significant degree in the handling/road manners department. All were a blast to drive to the grocery store or to a 2000 mile distant destination.
Put me down then as recommending you give the run flats a chance.