Thanks for the comments.
I think to sum up the differences between normal tyres and run flat tyres:
Normal tyres - Less noisy, more comfortable ride, better economy, possibly repair if punctured and cheaper to buy. No spare tyre with UX so would need roadside recovery or if repair goo used tyre would need to be replaced.
Run flats - Opposite of above but can drive with a puncture. Tyre would need replaced if run on flat.