I want to start by saying this is one of those essentials that every makeup artist I know keeps in their kit. It is amazing. It best used as a finishing product for makeup. Its cocktail of mineral and botanical ingredients lock your makeup on for the day, and give you a great boost of hydration.
It can definitely be used to prep the skin before makeup. It will give you a wonderful, balanced canvas to work on. It is not my first choice as a primer. I think MAC has a ton of other options that really are better suited toward that purpose.
I love the look of a glowing, perfected complexion. So, my very favorite primer from MAC is the Fortified Skin Enhancer, item 379837. The real joy of this product is that while it really works to perfect skintone and keep your makeup on, you never feel it. It uses a powder pigment that helps reflect light and control oil all day. And still, you will feel hydrated all day.
Prep and Prime Skin would be a another wonderful primer option for you. It is a silicone based primer that is going to add a great slip to the skin. You makeup would just glide on over the top, and stay in place all day.