Up until now I've had great luck with urlhasbeenblocked - extremely fast page serving with my Magento store, faster than Rackspace or Linode which was amazing to say the least. All of a sudden today it's been extremely slow, which means someone on my shared server hit the traffic jackpot. Nothing I can do I suppose other than request to get moved to another server. Anybody here have any experience with how long such transfers usually take?
When you run into an issue like that, the first reaction should not be "move me to another server".
First, while it's certainly likely that one of your fellow node users is being a dick, it could be due to some other issue that the provider can resolve.
Second, moving to another node will not necessarily resolve your issue. The other node might actually make things worse. In fact, if you've been extremely happy with your situation so far, odds are that the overall experience will be worse, as the cummulative load on the new node might be much higher then your current one.
You should notify the provider about the issue and let them investigate. If something is broken, they can fix it. If it is another user causing the issue, see if they can move them to a loser node, throttle him back, etc.
The people causing issues need to be dealt with, not everyone else. Otherwise everyone will just keep moving around and around.