Anyway, I finally found out my shade in MAC! For reference, I'm NC30 and purchased the Careblend powder in Medium Dark. I have the MAC Mineralize Skinfinish Natural in Medium Plus and loved it when I first got it, but stopped using it (the on and off/ changing up cosmetics thing : ]). Overall, I like the powder because it looks nice and provides a matte finish, but it's not completely matte. I don't know if it is nourishing my skin because I've been moisturizing more. It's also cheaper than the MSF Natural ($23 vs $29) for the same amount of product.
MAC Studio Careblend Pressed Powder in Medium Dark
MAC Mineralize Skinfinish Natural in Medium Plus
Left: Careblend in Medium Dark
Right: MSF Natural in Medium Plus
Left: MSF Natural in Medium Plus
Right: Careblend in Medium Dark
I'm sorry for the sucky swatch above (I didn't swatch heavily, but I guess it shows that it works with my skin tone lol!) but if you can tell, the MSF Natural has a pink undertone compared to the Careblend powder.