(Disclaimer - I'm a Google employee, I didn't work on this and my opinions are my own.)
I wouldn't say OpenDNS is evil. Offering an ad-supported free service is how many things are allowed to continue existing.
Avoid OpenDNS and IPS's that do this.
I couldn't get the ISP to budge and the client didn't want to change ISPs, so I ended up setting everybody up on some public SBC DNS servers I know about.
With all respect due to davidu, this "functionality" in OpenDNS has caused me to feel a raging hatred for it every time its name is mentioned.
Another worrying thing I noticed the other day is that they have a "feature" which injects an HTML header into the page you're requesting if you are approaching your bandwidth limit.
We all know that our ISPs are inspecting our packets, but it's a little disconcerting to see the pages you request manipulated in such a wholesale fashion.
Still, users having choice and forcing businesses to compete to win is good for end users and I support that 100%.
Not DNS redirection.
DNS redirection affects ALL programs that are trying to access a network address (obviously unless directly by IP). So when my Jabber/XMPP client tries to contact doesnotexist.example.com, being redirected to an advertisement page doesn't help me very much, does it?
Google Toolbar and Google Chrome defaulting to Google as a 'landing page' of sorts only affects your web experience and only when using those pieces of software. This is a far cry from Comcast's DNS servers resolving ALL DNS traffic that should return 'does not exist' to their advert-filled web servers.
If a DNS server presents an IP so you can show people a web page ( like Verisign did intentionally a few years ago [1]) instead of returning 'no such domain' (NXDOMAIN), you break DNS for all apps that expect a host that's not registered to not resolve. Verisign's screwup lasted 20 days.
I doubt Google would do this.