Unfortunately, last night I completely failed to remember that Rackspace and EC2 are direct competitors in this space so what was intended to be a simple data-p

Unfortunately, last night I completely failed to remember that Rackspace and EC2 are direct competitors in this space so what was intended to be a simple data-point may be construed as more than that - my apologies. What I intended to say was "you can make Cassandra work on EC2." However, if the I/O throughput of EC2 is a fraction that of some other provider, you'll need more machines in EC2 to achieve the same throughput. My personal site is hosted on the Rackspace Cloud and I've been very pleased with it, but my workload is different so I can't give a comparison. I also know that we've benefited directly from jbellis' support on IRC and the mailing list, so this should be considered an endorsement of Cassandra, if anything.