I'm an infrequent commenter but thought I'd share. I have used Latisse in the past, stopped using it, and then started again. I stopped because my derm stopped carrying it (no issues, she just wanted to have a medical only practice). I started again because my new derm carries it.
It really does work. I use one drop every other day or so, and apply with a non-latisse brush. You can find cheap very fine disposable eyeliner brushes on amazon or ebay. I drop my one drop into the lid of the latisse bottle and dip my little brush in. Then I line just the base of my top lashes. Any extra wetness on my brush gets applied to my eyebrows.
Last time I used Latisse every day, my lashes actually got too long and were causing my mascara to leave little marks on my upper eyelid. That's why I'm using it every other day this time.
I have not had any pigmentation effects in my light greenish blue eyes. I do have some very slight eyelid redness right at the lash line but I wear eyeshadow base every day anyway so it covers it.
I don't find a lot of thickening effect, just lengthening. So I still wear mascara and usually a bit of eyeliner.
The last bottle I bought was the 'six month' size for $170. So the way I use it (one drop per day at most) it should last a year or so. Worth it to me.