I had it with my second, and comparing it with my third, when I just had gas and air, I will be opting for it again this time if I can, defo took the edge off it for me, made me relax more in between and not think about the awful pain that was coming lol.
I did get an anti sick jab with it, so never felt sick, but I can say I enjoyed my 2nd labour, my third was awful lol.