I've tried 5-6 different types of self-tanners before, and have never really been pleased. I find the color is unnatural, the look ends up streaky/blotchy, and it fades strangely, with splotches at my elbows, knees, etc. I have medium-toned skin but can be pale in winter.
I was skeptical when I tried this, because the process is different than other self tanners (you put it all over while wet after shower, wear their included gloves and leave on for 60 seconds. It looks really, really dark while it sits on your skin, then you wash it off). Anyway, after trying it once, I absolutely loved the color and effect. Subtle tan, like I spent an afternoon in the sun. I used it again the next day and loved the cumulative effect. Best of all, no streakiness, no lines (e.g. at the neck) where the product color stops, and just enough natural color to look healthy, like I spent a day at the beach, but not super tan or orange. Added plus - it smells awesome, like chocolate, and not that funny self tanner smell that sticks with you. I was also able to towel off, apply lotion and get dressed right away after using it with no clothes or towel rub off.
I read some of the negative reviews, and I think this is probably just not the right product for people who want to be dark, or who religiously use self tanner most days; it adds more of a natural glow but I wouldn't say you're "tan." I suppose it might get someone much darker if you used it many days in a row, but I haven't tried this because it's not my preference.
Net/net: Definitely worth a try if you're looking for natural looking color. I bought for me, and I just bought for my friend for her birthday (who is very pale). 5 stars!