The Domed Shadow Brush by chance? I use that thing like crazy. I got the set last year and it took me a little while to use some of the others, but I did. I love the other shadow brush for creams. I use the brow brush for my brow powder and to do cream or shadow eyeliner and I use some of the smaller brushes to pin point conceal or get in the corner of my eyes without leaving a big old mess.
Sorry you are not having luck with foundations. I tend to go more toward the dry side and that has it's own set of problems too. What do you do? I hope the MAC will work well. I have heard a few pro's (doing tutorials) say to focus on finding a foundation that works the longest. You more than likely won't find one that works all day, but if you can get 5 or 6 hours without having to blot or set again, it's a good thing.
ETA: In other words, the "All Day Oil Control" claim is usually exaggerated or misleading, unless days are now 4 or 5 hours long. It's just like the reduces signs of aging in one week! There is no miracle in a jar, stuff takes longer to work, and sometimes going half a day before you have to touch up is a great thing. It beats an hour or two, and will stop women from throwing away several foundations because they did not last 10 hours or longer.