I had the opposite experience with a generic version of Ortho Tri Cyclen...I was able to lose weight and my sex drive went through the roof.
I'm in the same boat. I have been on tri cyclen lo for approx a year. In this year I have gained like 30 pounds and look 3 months pregnant constantly. (I'm not pregnant btw). My sex drive is basically gone and it hasn't helped my wicked pms problems with cramping etc. I'm looking to change to seasonique as well.
According to drugs.com known side effects of Seasonique are:
Acne; breast tenderness or enlargement; changes in appetite; changes in weight; dizziness; headache; loss of scalp hair; nausea; nervousness; stomach cramps or bloating; vaginal spotting or breakthrough bleeding; vomiting.