I've tried adbrite as both a publisher and advertiser. As an advertiser the traffic wasn't very targeted and had a low click through rate compared to adwords. As a publisher the amount per click wasn't very much (compared to adsense)
I haven't had any problems with them, but my payment is only about to mature. Unfortunately, the pay by cheque so I whatever I can I run from other ad network to avoid fees. The signature link pays well and pays Paypal.