I have adsense on four of my sites and I earn quite well.I earn around $1k from the oldest site, which is 6 years old.I am in process of increasing traffic to my other sites.
For me google adsense works great.I earn around 1k/month, but the problem is that I am stuck up at this level and I am trying out many things to increase.To reach this mark,I had to struggle a little and first 6 months,I made absolutely nothing.I am happy how things are shaping up. My suggestion is to go for google adsense to make money online.