Yep, I have the SS109 but not the MAC 109 so I can't do a straight comparison but the other brushes I have that I have in duplicate with MAC have been the same, if not better. I like my SS239 better than my mac 239 because it's a bit fuller at the tip but all the rest have been exactly the same.
That said, I have the individual brushes and the travel set- the travel set bled a little and shed a couple of hairs out of the SS187 and SS168. The individual brushes have all been fantastic though, not sure if they are the exact same as in the huge set, I'm assuming they are though.