Details from Benefitcosmetics.com on why do they love the product:
This industrial-strength concealer camouflages dark circles, shadows and discoloration for a seamless, natural-looking finish without creasing or fading. You name it, boi-ing helps hide it! Available in three shades…when in doubt, choose boi-ing 02 – medium.
How to use it:
With fingertip, dab boi-ing on the darkest areas you want to target…underneath each eye, at the inner corners by the bridge of your nose, or over any other flaws. Pat gently outward to blend
Their tips:
Pat concealer between your thumb and fingertip to warm it up…it will glide on more seamlessly.
And I got no.2  . . . but it does seems too dark for my skin, maybe I should use no.1. Nevertheless here is my review. The texture is thick alright and I need to learn how to use it. I think a brush can help me out for the application-wise. Regardless since the tips is involving finger tips I don’t think it would be a problem using your hands.

There is no scent and it’s just a plain concealer . . . I think.

Here is my hand, there’s a dark brown spot there, and this is the far most extreme concealing, but I just want you (my beloved readers) to see the before and after application in the darkest spot ^___^.

It does help the coverage by by 70%, I use it on my acne and it does give the acne a red-less look but the bump is still there. For under eyes, I suggest using your ring finger and gently dab it but again like on this dark brown spot the coverage is not 100%. Depends on the severity of your condition, so for dark eye circle, depends on the darkness level. For covering large pores, it work really well on me and so far those are the reason for me to use it, hmm maybe some fine lines too. I like the fact that the product is light and looks soft on the skin, giving me a much more smoother look.