[David]

I run tubeless on my road and MTB. Most punctures on the road bike are so small you either don't know you got it or you hear air loss for a few seconds and it then it seals back up. I still carry a tube just in case and have had a few tire cuts that were too bad to seal themselves. One problem with a tubeless road tires and big cuts is that they're flat in less than one revolution so you need to have decent bike handling skills. I've also had cuts that were so bad I had to tear a piece of bar tape off to cover the hole so the tube wouldn't stick out.

MTB tubeless is almost a must have these days. You can run really low tire pressures for traction without fear of a pinch flat. If you're far from home, vehicle or support you just carry a tube.