I recently had a massive acne breakout (over the course of three months) and am now left to deal with the scarring. Originally I used one of the old Becca duo concealers that I still had lying around. While it covered well, I found it a little to thick, a little to greasy and a little too cakey.
I bought the NYX concealer on a whim and use it on my cheek where all the scarring is. You can now barely see anything. I use my foundation over it and my face looks smooth. The concealer is easy to use, doesn't look cakey and isn't greasy. It's also the right shade of orange for my skin tone (NC50 in MAC, Polynesia in NARS, 13/Sienne in Lancome, Sandalwood in Becca, 4.3 in Smashbox). The other's I've looked at are slightly too pale and would show up under my foundation. This one doesn't show up at all - not even over the course of the day.
I wouldn't use it under my eyes as I find it a little too thick for that. Besides, my MAC Pro Longwear and NARS Radiant Creamy Concealer do a fine job under my eyes.
If I ever ran out (before the scarring finally disappears), I'd repurchase.