DH used to ride tubular clinchers (Tufo??)- tubular tyres that have the ridges to mount on clincher rims.

Rode very nice but there came a puncture in which the tyre deflated and he had to call the sag wagon (his Dad in this case). Although the tyres fold up, its definitey easier to ride with a tube and a CO2 cartridge.

He's back to clincher tyres now. I think unless you are riding at elite level and can have a spare wheel in the chase car, stick with the easier to change clinchers.