This look really useful: only use the potentially high latency consistent read operations when you really need them.

BTW, I have noticed something that one of my customers concurs with: using SimpleDB remotely has extremely high latency (while not running on an EC2 instance). This increased latency seems much larger that hitting a Rails app on port 80 using HTTP. Anyone have an explanation why remotely hitting SimpleDB is slow but hitting a web site hosted on an EC2 instance is fast?