Widget Bucks is too new to judge and definitely not comparable to AdSense which is well established and proven. Just my 3 cents
i dunno but I think if you put it on your pages your google rank plummets: http://www.shoemoney.com/2007/10/24/why-does-google-hate-widgetbucks/
lol Funny! anyways WB is not worth everyone's time unless they ACTUALLY pay. Once its gets crowded just see how CPC goes down the drain. Dont be surprised to see 0.05 cents clicks.
I've had 1000 impressions here but no clicks. In the same time I've had about $.90 from AdSense. My $0.00.
It's more suitable for product related sites (review etc). I agree with kentuckyslone. It's too early to compare adsense to widgetbucks.