A sudden front tire deflation (blowout or pinch flat) can make the bike hard to control. But that's never happened to me (touch wood). Usually with a punctured road tire, sometimes you'll hear the hiss of escaping air - depending on the ambient noise and how quickly the tire goes flat. Then you just feel the road very...directly. When you're riding on a 110# tire it doesn't feel like it's giving you much cushioning, but when it goes flat you realize that it was smoothing out the road quite a bit.

I've only ever gotten slow leaks on my fat-tire commuter. I think the tires are so much heavier that by the time something works its way through the tube it can only make a very small hole, and of course with the lower pressure, air doesn't get forced out as quickly.