This is one of the very few products that I haven't questioned buying over and over and over again. I don't actually wear makeup on a daily basis (most days I just wear moisturizer, sunscreen, and this) and this product is about 90% of the reason why I feel comfortable with that. It smooths out my skin and gives it a matte finish that lasts all day, and it doesn't make my skin go red like a lot of other products do. (It also doesn't break me out, but I'm not usually prone to acne and it normally takes a lot to break me out, so definitely take that with a grain of salt). I should probably note that I'm 22 so I don't have many lines to fill on my skin, but I really do think this does a great job of filling pores.
Of course, for a drugstore product, I definitely feel like this one is on the expensive side of things (with taxes it's almost $20 CAN) and I find myself running out of it more often than I would like (though I do literally use it every day, so maybe I should be surprised?) but, unless a cheaper and better version of this comes along, I can't imagine not repurchasing it.
Also, I feel like I should warn you that this product looks really, really gross by itself- I have a feeling it does such a good job at filling pores because it lowkey almost looks like something that you would pop out of a pimple and it doesn't really look like something you would want to put on your face, and it almost feels oily when you first put it on but, once you get past all of that, I've found that it really does work brilliantly.
EDIT: I also just realized that I didn't actually mention how this works as a primer when I'm wearing makeup SO- When I'm actually using this as a primer, it's always worked great for me. I'll do my usual moisturizer, sunscreen, primer routine, and then I'll give it all a few moments to set in before I put finishing powder on and then start with my foundation etc. etc. etc. and I find that whatever I'm putting on goes on incredibly smoothly, and manages to last all day before I need to touch it up or (at the very least) do some oil blotting. Really, I don't have any complaints about this product and how it's worked on my skin!