Smooth on makes great stuff, it's just really expensive. There are a lot of other companies that offer comparable products at much more affordable prices to be honest.
The thing about smoothon is they use a lot of 'fillers' and some really.... nasty ingredients. Tuns of mercury, and other dangerous things.
I personally prefer alumilite, both for quality and for the safeness of the products, however, smoothon has some products you just cant get anywhere else. And for those, i use smoothon