I haven't tried that brush set, but I do have a couple Smashbox brushes. I have the Powder brush, Foundation brush, slanted eyeliner and cream eyeliner brushes, and the brow brush.
I love, love, LOVE the Powder brush. The foundation brush is ok, I think I like my MAC foundation brush better. The slanted eyeline is wonderful! I use it with their Jet-set waterproof eyeliner to line my inner rims. The cream eyeliner brush and the brow brush are really nice also.
If you want to try their brushes out, the Beyond Beauty set would be a good deal, so would the Studio style set. It just depends on which brushes you would use the most.