time sensitve: comparing performance to MySQL

Hello,

I've been tasked to do some quick research on Postgres vs. MySQL that I
need to present later today. I've already done a lot of Googlin' and
reviewing of the Postgres websites.

The project at hand will be a  high-volume website with many complex
queries. It will likely use replication. Performance will be most
important for SELECT statements.

The project will be ported form an existing codebase which uses Oracle
as the backend.

I understand that Postgres has been closing the speed gap with MySQL,
but I'm having trouble finding hard data on this. What specific
information is available in this area?

Your help is appreciated!

--Matt