Over 10 years of driving, I have had one puncture which was a few weeks ago in my E91 with runflats. It was more a tyre failure, which resulted in very sudden pressure loss at national speed limit, and I was thankful to have the runflats, as I subsequently nursed it to the petrol station 5 or so miles up the road.
However, it was a Sunday, so couldn't get to a tyre shop to get a new one, and nearly had to be towed from Dorset up to Nottingham. In the end I borrowed a space saver from AA, and drove back to Nottingham at 50mph with my offending tyre/wheel in the boot. In short, I don't think there's ever a replacement for 'normal' tyres and a spare.
In all, do I think runflats are handy in the worst case scenario? Yes. Is the worst case scenario likely? No. Even with runflats, you can still be in the position I was in.
Armed with all this information, I still opted to replace all 4 tyres with a set of Toyo Proxes non-runflat. They are about half the price and offer a number of improvements to ride quality. In doing so, just make sure you have a puncture kit or breakdown cover and you should be good to go.