I used gas for all three of my births, and all three were inductions - so I was hooked up to a monitor. Dh could read the machine and knew when strong contractions were coming, and told me when to breathe.
With my first I also had pethidine, so was quite out of it. With my 2nd and 3rd (no peth) Dh kept turning the gas down, as I know he wanted me to be in control.
I agree with some of the other ladies, it was great for biting down on