I was on Alesse for 3 yrs or more, and really liked it. I didn't gain any weight from it, and it stabalized my moods. However, in the last year or so I experienced spotting the week before my period. It wouldn't happen every month, but it was off and on. Nothing too serious, just more of an inconvience than anything. But just recently, I had an experience on it where I need to be switched off Alesse. I had my regular period and then a week later, I was having break through bleeding. It was like I was having a whole other period, except it was heavier than normal and I had bad cramping too.
The doctor, suggested I switch to a higher dosage, cause Alesse probably isn't strong enough for me anymore.
So, that's something for you to keep in mind. Most girls I've talked to experience break through spotting, because it's an "ultra-low dose pill". But I loved it when I was on it, but I guess you'll have to see for yourself.
Good Luck!