I know it's annoying. I took the mini pill while breastfeeding my son and had breakthrough bleeding for the entire 2 months!!! And I hadn't even had a regular period yet.
However, I have a friend who got on seasonale, and she had alot of breakthrough bleeding at first. Especially around weeks 4-8. She was fed up. But after the first cycle, her body magically adjusted and she hasn't had any since and absolutely loves the pill. Her doc said that any time you are supressing your periods you have the risk of breakthrough bleeding until your body adjusts to the new schedule. I have heard alot of stories from seasonale where the breakthrough bleeding subisided in the first couple months and they ended up loving the drug. I wouldn't give up just yet if you're really into the 4 periods a year thing. It takes time. If you're not, and you can't live with it, by all means, get on something else.
I will probably try seasonale after this baby. My favorite birthcontrol EVER was NuvaRing.