Loooove this stuff!! It really helps eyeshadows (low or high end) go on smoother and last all day. It actually works as advertised by Too Faced in that it does intensify the colors of their own eyeshadows. I find it really doesn't have that same effect with other brand eyeshadows though. I have the one in the light blue bottle that has a yellow tone to it and the yellowness cancels some of that reddish purple look on my eyelids. My eyelids are not oily at all so I cant say how it holds up against that. I believe UDPP is the #1 pick for oily lids but I havent tried it since I'm not oily. I swatched UDPP on my hand once and it literally seeped into every crack in my hand (so def not for dry skin)
Anyways, the best trick I learned abut this product was from one of my fave youtube beauty gurus lovemelisamichelle when she used some eye primer underneath her eye. So I tried that with this and it works awesome!!! I have very dark under eye circles and again, the yelllowness cancels some of that out but it really helps my concealer go on smooth and last all day!!! its a miracle.
I wear contacts and have allergy eyes so my eyes water a lot and I rub them. Also, one of my eyes sits in my socket slightly further back and this increases the dark shadow there and that same eye also has some light freckles on the ocular bone which also creates a darker effect that drives me nuts cause the other under eye looks lighter :( This product helps the concealer cling, go on evenly and stay so much better. It worked super great with a Sonia Kashuk stick concealer but that tends to look dry under my eyes after a long day. I've been using Maybelline Fit Me concealer under my eyes for a week and it glides over the primer and lasts pretty darn good too. (Not as long as the drier stick concealer but I'm still happy with the combo)
Side note - if you have allergies to bismuth oxychloride then dont apply this to close to the lash line. I am sensitive to bismuth and it made my eyes (both upper & lower lids) really itch at the lashes when I worked it in. Now I stop right before the lash line and no more itchies. Porblem solved!
Overall, I think this is a definite must-have in any makeup kit, you will get more bang for your buck out of any eyeshadow, and I will for sure buy this again.