It is a godsend! It doesn't look thick at all even after building up. As long as you have the right shade, which I recommend going to your local Benefit counter to get matched.
I have some old acne scars on my cheeks and it does hide them pretty well. I am pretty smooth and clear on the rest of my face so what I do is spot coverage with the sponge on the scars to give them more camouflage...then I sweep the rest of my face with it using a powder brush....I don't use the brush that came with the compact because I think it sucks (it sheds!), so I use the powder brush that came with my Benefit Betty Brushes Up on Beauty makeup bag. I find that not using the sponge all over (if you don't need the added coverage), makes the product go further...which I like coz the $34 is tough on the wallet!
For even more coverage, I use their You Rebel tinted moisturizer beforehand which looks nice and still natural underneath the Hello Flawless.
I did replace the sponge it came with after a month or so of daily use, to keep it all hygienic and stuff. I bought Sonia Kashuk from Target's square makeup sponges as a replacement and works just as well. Not sure if Benefit sells replacement sponges.