Malcolm, I reckon the latest gereration of runflats, like your Contis, ARE an improvement over the older versions, but still not on a par with a good performance non R/F.
I came from Runflat 16's and found them quite acceptable on my R53, even with the power it was putting out (210+), probably because of the taller 55 series sidewall which absorbed more of the bumps and surface changes, but when I moved to the R56 with 17" runflats, I did notice a deterioration in ride quality and that the overall 'comfort zone' of the tyres was narrower than the 16's - ie on smooth dry roads they were fine, but they just didn't feel that 'secure' when pressing on in less forgiving, cold and/or greasy conditions. The combo of the overly-stiff 'Sports' suspension and the R/F 17's just didn't seem to gel. The JCW Suspension helped a bit, but the power increases seemed to upset the applecart again. I can only report what I found when I switched to the non-R/F Contis. My car now feels more 'at home' doing what it's supposed to do - ie going down an interesting bit of road at an interesting rate without scaring the crap out of me. The combination of my JCW and other power upgrades and my JCW Suspension really showed the R/F's as the weak link in the chain, and in fact I wish I had changed the tyres before I did any other mods...
The only fly in the ointment is the dreaded 'puncture scenario' - I do miss the peace of mind the runflats gave - but I'm willing to risk that to enjoy my car more of the time, and me Werther's Originals don't bounce out of their packet!