Now I usually have 2 on the go, a cheap and cheerful one and a fancier one and do one of each a week.
I second the Simple one as my cheapie. The advantage is that it only takes 3 minutes. Its great for when you know you should do one but don't have much time. It also doesn't cause much disruption to your face. Its easy to get off and so cheap you can easily use it twice a week.
I like the Eve Lom one for more serious moments. Smells fantastic and also feels good on. Quite thick and you have to scrub to get if off. I think you have to lie down for 20 mins or something which I'm sure adds to the beautifying effect.
The origins black clay one is just too messy. The Dr H ones are ok, but I wouldn't go out of my way to recommend them.