They're evil for providing global DNS you can use from anywhere because of something verisign did? And their service is terrible because its not quite as fast as your ISPs DNS which is much closer to you? Bitter much?
People like OpenDNS because you can set and forget it, as you move around networks. Its nice. If you don't like it, don't use it. But spare us your outrage, mm-kay? ;)
My shitty ISP's DNS is only slower than OpenDNS on my ISP's awful internal network that routes my DNS packets over it's internal network cross-country for no reason -- on the internet backbone OpenDNS is marginally slower. Both are completely blown out of the water by Level3's free public DNS (4.2.2.1 - 4.2.2.6).
OpenDNS's claims to speed are bullshit, and they don't even seem to try -- I've only ever seen packets routed to them via NTT/Verio, which is the least-connected and highest-latency Tier 1 Network.
It's not fast either: http://news.ycombinator.com/item?id=497959
I don't know how the hell they managed to market themselves so successfully as the answer to "my ISP's DNS sucks", especially when their entire business model is so straightforwardly evil: http://en.wikipedia.org/wiki/Site_Finder