there is no clear winner. different ad agencies work better for different niches and different sites. sometimes ypn blows adsense out of the water, and sometimes vice versa. sometimes a second tier program may work as well. the only way to know for sure if it will work for your niche and your site is to test.
Cheers Your right in saying depends what you want I need to make click revenue like adsense but with alternative because I am banned of course by Google for clicking 6 times testing my ads. So I need best alternative to cover hosting for a free site. Thats paid every click like adsense Looking at text link ads now
depends on the specific program's TOS. usually, though, you can only have one contextual ad unit type on each page. that doesn't mean you can't have different networks on different pages, or even on the same page with a reload, though.