I have the rare situation where I have a lot of content on each page, so the three ads allowed by Adsense don't dilute the content very much. I've used Media.net for over a year now and their revenue has increased over the months to where it is about 30-40% of Adsense. But most pages have 6 to 10 Media.net ads.
I would say that Media.net makes sense to supplement (add to) AS, but not to replace.
The MN ads that I see looking at my pages are pretty bland, compared to AS, but I think they occasionally place better looking ads for some users.
I've tried SwithAds as well, and they have better looking ads, but they only pay for impressions and it would have probably taken a year from me to get to the minimum $100 payout.
I've also used Amazon ads, but am getting much better income from AS and Media.net, so I've dropped them from the slots that I can put AS and MN in. I still have a product associated slot that gives me about $10/mo.
Side question. There is no "Bing Ads" anymore, right, it just diverts to Media.net, right?
[edited by: martinibuster at 3:45 pm (utc) on Sep 11, 2014]
[edit reason] Removed commercial solicitation. [/edit]