Paused my Google Adwords campaign

Too many clicks were generated by what looks like fraud. Looks of clicks with 0 time spent on the site. When I compare this to the traffic I get from MSN's web site, MSN gives me much better quality clicks with higher time spent on the site at a much lower cost. Google Adwords offers more functionnalities for choosing visitors by profile, but in the end, the fraud kills it and I don't have the confidence in their fraud management system (I got a nice email from Google on how they do it, but it is not convincing enough) to think that I get my money worth with Google. 

nb: I stopped advertizing with Yahoo long ago because their ad system looks like from another century vs. Google's or even MSN's.