the reason for different opinions is because of the different types of domains people have.
overall, i think sedo beats any ppc no problems. simple reason is high bids and , the largest number of advertisers. because google ads, almost any keyword or combo will bring up relevant ads. this = higher click rate. for those with a lot of traffic even a small increase in click rate results in much higher earnings.
(example fatpeoplepics.com - i can use ' fat people pics' as a keywords and there would likely be fat people adverts - .. just an example ) you cant do this with other ppc providers.
fabulous is the best for gambling. and soemtimes domains that dont seem to work well on sedo. one problem is a limited advertiser base. difficult to find an exact match for your domain. this is true for almost every other ppc company. (apart from the big overture etc. requirements very high)
domainsponsor is similar to sedo, but not as good , in my opinion.
the ad links dont look as good, and more difficult to manage/stats etc. payment by cheque, ? not good if your not in usa. sedo is good for bank transfers with a lot of money. i wouldnt trust a cheque posted internationally for a large amount of money.