postgresql vs mysql performance comparison

I’m interested in comparing the performance of postgresql and mysql

on various combinations of user loads and database sizes.  I have seen

a few statements to the effect of “mysql is faster for small, low use

applications, but postgresql is better for bigger stuff”.  I would like

to run some independent tests to see if this is true.

Before I do this, has anyone done this already, with the latest

versions of both?  I think I’ve seen some comparisons that are

somewhat dated.

Does anyone have any pointers on what to do or not do?  Or

would anyone be willing to comment on an experiment plan

and suggest improvements?  Any help or references are appreciated.