The issue of VM censorship would be a valid reason to change but I'm curious how the speed of anyone's DNS servers can matter. I'm not a VM customer but unless their servers are taking significant fractions of a second to respond I can't see the problem. Your computer(s) will probably be caching the results anyway - it's not like you'll be firing off hundreds of queries a second. It's more likely to be half a dozen an hour. If that.
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Andrue Cope
Brackley, UK