I saw the difference this mask makes on my skin after one use and was very, very impressed. Like other reviewers have noted, it just adds visible life and luster back to your skin. It doesn't irritate my sensitivity (underlying mild rosacea) and actually reduces redness. I often leave it on for several hours or even overnight. I *think* you may really get maximum benefit in 20 minutes, though, just like the instructions say.
I work at a shop that sells lots of very nice skin care lines (but not Dermalogica.) Recently we had a training on one lovely high-end line that we sell. Before I went into work I used this as a 20-minute mask. At the training, the esthetician was talking about healthy skin and singled me out. "How old are you?" she asked. I told her my age (45). She balked and exclaimed, "You have the skin of... a child!" Now, I see all the flaws in my skin of course but other people seem to think my skin looks pretty good. I don't attribute all of it to just good skin care, but MultiVitamin Power Recovery Masque does what it promises. It is extraordinary.
If you're seeking radiance, you deserve to try this for yourself. We need more luminous skin out there! : )
2/28/15 Edited to add: I still definitely enjoy this mask at times when I want to look my best. I don't think it's the vitamins in this mask that give results, but the peptides, and they are the sort that work for some hours after application but don't really impart long-term benefit. So, in my experience, it's like a fairy godmother product: you look radiant for the ball, but still turn back into a pumpkin in the end. It's a deal that I'm willing to make, and I still give it 5 stars and strongly recommend it. You just have to understand what it does and does not do.