Both, the pad for the client is larger and has plenty of room. The stool is fully adjustable, but occasionally because the client is in the comfort of thier own chair 'with thier feet up' they can be a little low so I take an extra cushion for them to sit on to help with levelling it out, it's rare though. Best bit of kit for being mobile I've had to date, practical and light, I've only had the Darley pedi-stool, so no idea how the others perform.
Darley recently upgraded the clamps on the stool, i'd worn mine out(kids sitting on the foot pad!) and rang them up to get a replacement stem and clamp, sent them the part and they sent back the upgraded version for free.
The biggest thing for me though is being able to get the right posture, and with a pedi-stool, sitting up-right it seems to be working a treat.