I've been using tubeless on the road for three years without a flat (tempting fate, touch wood, etc).

I use tubeless specific rims and tyres (Shimano / Hutchinson) but I know people who successfully use Stan's conversions. Your LBS can advise on suitable rim/tyre combinations.

I renew the sealant every spring and, so far, haven't found any evidence of punctures, but I've seen plenty of tyres that seem to have received multiple holes and the Stan's sealant has formed a small plug inside the tyre and done its job.

The system also eliminates pinch flats.

There are other advantages such as lower rolling resistance and a smoother ride because it's possible to run as efficiently at a lower pressure.

Okay, sales pitch over ;-)