I think you are making an assumption regarding availability vs price vs demand. I would think that given the sort of capacity Amazon has, at some point of time the cost of a spot instance would be the same as or higher than the cost of a regular ec2 instance, at which time it would make more sense to just get a regular instance.<p>Per my understanding the attraction of spot instances is that you can get short-term instances at lower rates. Even as I say this I am making a big assumption that Amazon's spare capacity is much larger than demand for sport instances.<p>Finally slow ping times could be caused by any number of reasons, attributing them to one particular cause based on a coincidental date might be a bit much.