I have decided ! Once I hit the $100 check from Adsense on my blog, I am off to Adbrite. It looks better and from reviews, Adbrite gives better. What do you guys think? Should I do it? Adsense gives me nothing.
Adbrite will depend on your site. If you site is doing really bad for adsense Adbrite probely is not the answer.
I would not close your Adsense account. Just try 50/50 and see how it goes I would thing this would be the best way of doing it. If you don't try adbrite then you would have never known how it would have performed, so it's worth a try.
Like John suggested, a 50/50 split test is a good idea. Then you can see which one performs better, and keep that one.
Yes, I can heartily recommend AdBrite as an alternative. In my experience it's best to use AdBrite inlines in combination with AdSense on the same pages - increases your earnings by maybe 20-30% if you get it right. If anyone's interested please consider using my bottom right sig link (Banned by AdSense) to sign up!
It is not recommended to close the adsense... Let it be. But you can also try adbrite and bidvertiser.