I took Zoloft for 4 months after my son was born. I am prepared to take it again when my 2nd is born if I have the same PPD like last time.
I do not recall experiencing any side effects, but my situation was a bit different, since it was right after giving birth. (For example, I lost weight because of that, so I am not sure what impact Zoloft had on my weight.) I know for a fact that I did not experience what the first poster mentioned about feeling crazy for 24 hours.
What Zoloft did for me was enable me to cope better. I did not get near as overwhelmed by things as I had been getting. After 4 months of being on it, I felt like my old self, so I slowly weaned myself off. DO NOT go cold turkey off any anti-depressant! I took 2-3 weeks to cut down on my pills until I finished them up.