Hi Brynn,
I suggest the Well-Rested SPF 20 Eye Brightener (loose shadow version) for dark under-eye circles. I have all three products: the powdered concealer, the powdered Well-Rested, and the liquid Well-rested. The concealer is really great for red marks, sun marks, or pimples. It neutralizes the color and works well under a foundation. If you have acne or get zits, it's a great thing to try! The Well-Rested Brightener (powder) lightens dark places and provides good coverage. The liquid version does not work as well for me (less brightening, less coverage, harder to apply). If you wanted to choose only one product that works really well for dark eye circles, I highly recommend the Well-rested SPF 20 loose powder shadow. I also have very sensitive skin, so much so that I cannot wear all BM products (e.g. eyelid primer, big and bright eye liner, etc), but the products you're asking about work really well for me. Hope this helps!