Purchased this based on an InStyle review, although I generally always love MAC products.
This works well and I do like it. I do wish it had a base nude tint to it, but that's just my preference. Otherwise it's a really nice product and a good base for lipstick and glosses.
MAC prep & prime works to help lipstick go on smoothly, keep lipstick from bleeding and make lipstick last longer. All it takes it to apply prep & prime to lips before applying lipstick. My tube is a little jerky when turning it up to apply product, but it works fine. Prep & prime is an essential for me.