I took the pill for 2 years, followed by 2 years on depo, and then back to the pill for the past 3 years(first was progesterone only as BMI too high for combined, then when I lost weight back to original combined pill). I have to say that my weight problems really started when I first went on depo (hence being unable to go back on the combined pill after) and I think that it is partly to blame, although I did start uni at around the same time and that was when the weight began piling on!!! Since coming off depo and getting back on the pill I have lost lots of weight and am continuing to lose. I don't believe the pill causes weight gain or hinders weight loss (or at least for me anyway), although maybe depo does. I felt very emotional on depo and not having periods made me feel liberated in some ways but I believe it affected my pyschology in a negative way.
Just my experiences xxx
PS I should add that I have been on 2 different types and 4 different brands of pill and have found none of them have been a problem with regards to weight.