I take Seasonale, and I have my period every 3 months. I've been on it since February. I had a little bit of spotting during the final month of the first 3-month cycle, but I haven't had any spotting since then. My doctor said it's normal to spot during that first cycle, until your body gets used to it.
I get very irritable during PMS, and I suffer from migraines during my period, so it's wonderful to only deal with it 4 times a year. I've had no weight gain or anything like that. I've been extremely pleased.
I would be happy to answer any specific questions you might have.