In terms of coverage, it probably depends on how much you want to layer and how the mineral foundation blends in with your natural skin. I found Tarte's to be a bit sensitive to my skin condition on day to day basis, because if it was slightly too dry, it would show up on my pores. Also, when I put certain sunscreens underneath, it would create a bit of a problem for some reason. It's a very light coverage foundation, which can be buildable, but it's a bit tricky to work with in my opinion. Laura Mercier, on the other hand, has the perfect coverage I need which is light-medium. I want to even out my skintone, cover some light spots, but are okay letting my darker scars show. So in terms of coverage and texture, Laura Mercier is a win for me.
Another thing to mention is the brush. For Tarte's airbrush foundation, the Airbuki Bomboo Powder Foundation Brush that's sold separately, is almost a must. I personally don't like that fact that I would have to buy another brush along with this already pricey foundation, but the brush itself was extremely dense and worked very well with the foundation. I also like the fact that it's fairly small which is perfect for travels. I used the Real Techniques Buffing brush with it before and it didn't blend into my skin very well. On the other hand, Laura Mercier works wonderfully with this brush. This foundation is more flexible in the tools you use which is a plus.
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