I've had two inadvertent dry tanks:
First time, I was distracted and forgot to change; it coughed once, ran fine for a while, coughed again and sputtered while I franticly scanned the panel, as I was descending and about 2500 agl over the bumpy part of central WV. Saw the clock hands 20 minutes past each other, threw the selector and had a smooth landing 15-20 nm away.
Second time, my fuel stop had pump problems and couldn't deliver fuel. I was sure I had plenty for the trip, but wanted it all in one tank for descent and landing. I was watching the clock, the fuel gage and the fuel pressure. Reached my last-figured change point, thought I could make the extra 3 minutes to Top of Descent. Nope. No cough, no sputter, or fluctuations of any kind, just silence and a significant pitch down at 9500 msl that my wife didn't appreciate. So I threw the selector and it restarted almost immediately. Filled up with 40 gallons, meaning I landed with 12 gallons in the one tank, good for 1:20 more flight time.
Last weekend, I thought I had magneto issues in cruise (9500 in clear but darkening skies). So I tested it, turned the switch one click left and it quit--silence and that pitch down again. Turned it one click back to Both and she was immediately running again. Turned it two clicks left, she kept running, and I left it there.
Three restarts, two at 9500 msl, the third one maybe half or a little less. Nothing to it, no delays, no fuel pumps, no drama.
Then again, I don't panic about changing tanks anyway. It's always nice to do within a reasonable distance of an airport, if there's one around, but I wouldn't deviate or wait to reach one; I also lean down and turn the selector (fairly rapidly) without turning on the electric fuel pump. My Owners Manual doesn't say anything about that, and recommends running the first tank for an hour, then running the second tank dry as a regular practice. No thanks, I'll keep changing hourly.