This really would not be all that surprising, but it also would not surprise me if the average Postgres setup was better tuned/architected than the majority cas

This really would not be all that surprising, but it also would not surprise me if the average Postgres setup was better tuned/architected than the majority case of MySQL uses. Our setup was surely not ideal, but even with significant tuning, it was not sufficient. It is really good to hear successes like Reddit's, though. How long have you folks had your databases in EC2?