Sigma F80. Also, if the MAC 190 is like this Sigma one, I would definitely not recommend spending that much money, as there are many dupes of that brush available.
Although I love Sigma brushes for the most part, I found this brush to just be pretty average, my main problem with it was that the bristles were too thin feeling. When I apply it to my face the bristles have too much "give". What I like about the Revlon brush is it feels stiffer and less flexible, like there are more bristles to it, as it doesn't bend too much during application. When brushes like are too flexible, it can mean a streaky application.
Do you have this brush, do you like it? Do you use foundation brushes like these?