It is partially true. Just like Adsense , Kontera also targets keywords and the earnings very much depend on the quality of those keywords. On the other hand, I don't see any problem if you put both adsense and Kontera ads on the same page. FYI : I have already used this combination and it works fine.
Although there's no conflict of interest between those two ads network, I would rather focus on only one rather than spreading my earning between two.
Using Adsense and any other system would not normally "spread" your earnings. for most people, combining ad networks INCREASES earnings.. Unless one of the two leeches CTR from the other - which in my case with Kontera, has not been true..
Kontera is okay as a complimentary monetization method but the payouts are MUCH lower when compared with Adsense. If you have high traffic volume on your site then it could be worth it.. or if you have a lot of sites, but if you just have a couple of sites that don't get tons of visitors you would be waiting a long time for a $100 payment. - Dean
kontera doesn't slow down your site's loading - unless you don't ask your account manager to optimize the coding.
Speak for yourself.. Kontera out-earned Adsense in November on my site. and so far this month, it has earned virtually the same.. How Kontera (or any ad network) performs on YOUR site depends on many things. I also never noticed, nor have ever gotten any complaints about Kontera slowing down my site.. I guess my point is: Try everything, keep what works for YOU.
You have a popular site, kontera might be giving you good ctr/ecpm, unless kontera gives the regular publishers/bloggers a decent amount per click, i don't think a regular webmaster will say any good about kontera. I have personally seen that on a general site/blog kontera pays lot less, [90% SE visitors and most from US] so quality of visitors is not an issue. On niche blogs kontera pays a bit more, still lot less than adsense.
Tearabrite, Kontera, generally speaking has a much overall lower payout rate than Adsense. I know that because I have tested it across a number of niches. That said, your stats are your best ally and you've found that Kontera works better for your site/niche. More power to you and I agree that people should try several things and stick with what works best for them. Dean