I bought the Stretch Mark Concentrated Cream (in the tube, not the pump bottle). I like the thicker texture because it forces me to take the time and massage it into the skin (and research shows that massage does more to prevent stretch marks than any lotion or cream alone can). I also like that it comes in a tube, which is easier for travel.
I used this all throughout my first pregnancy, from the week I knew I was pregnant until after I fit into my old jeans again. My mother and sister both had a ton of stretch marks from pregnancy, though neither of my grandmothers have stretch marks from pregnancy (my mom calls hers "tire treads" because they go from her bikini line to about a hand's width above her navel) and none of them used any creams or lotions for stretch marks until after they appeared. So I was dilligent about applying this every day and twice a day in the third trimester. I did end up with a few, very small dot-like stretch marks low on the bikini line in the final weeks of pregnancy (my daughter was two full weeks early), but other than that I was thrilled with the results, seeing that genetics were against me.
I am currently pregnant with my second child and have entered the third trimester, so I'm applying the cream twice a day, again. I'm already a little bigger than I was for my first baby, which is typical. So far, no new stretch marks, the ones from my first pregnancy have only re-stretched, but, from what I can see - and I can't see very much below my belly button - they have not gotten bigger.
I actually have more stretch marks from puberty (on the sides of my hips) than from pregnancy. I wish I had known to use this cream when I was a growing teenager.
I cannot really say how much of my success was due to the constant moisturization of the skin prior and after stretching, how much should be credited to the massage motion, or how much I may thank or blame genetics. I didn't expect miracles, but I am very pleased with how things have turned out so far. I am also glad that I do not have to shell out a ton of money for a rich cream. Still, I will not stop using this cream until after I fit back into my old clothes, and I will use this cream with any future pregnancies.