I'm in the look out for an outsourced DNS too.
I don't want keep my own DNS server and also don't like to migrate hundreads of domains to a new provider every time we change hosting.
So an outsourced DNS provider would come quite in handy.
But I was surprised to find out that there aren't many options, at least my google searches didn't turn up all that many.
And most of the options are too expensive or old and cumbersome websites suchs as DynDNS.
I found out though that Rackspace is planning to launch this kind of service soon, coupled with their cloud solution. I'm looking forward to that.
I also found out that He.net is offering a beta for free, which I signed up for but didn't like their interface too much (falls into the cumbersome / old website category).
Another thing I noticed is that the usual pricing is simply crazy, some providers want to charge per domain (in other words per zone).
Well, my reason to use their service in the first place is that I have way too many small domains to migrate every time I switch hosting.
If it was big domains I could afford to keep my own DNS servers and wouldn't need them.
Or if it wasn't that many domains I wouldn't need a DNS outsourcer in the first place, as I could migrate them easily.
Charging per domain is a deal breaker, plain and simple.
It's so ridiculous indeed that in such a pricing model it would cost me more than my hosting itself.
It would make more sense it they charged per queries only.
$0.50 per million queries – first 1 Billion queries / month
That's the Amazon rate per queries, sounds reasonable to me.