I am deploying my first geoserver in production. I develop on a Macbook Pro retina, and my client uses Windows, so I deploy on Windows servers.
My first impression was that geoserver seemed a lot slower on the Windows server than my development machine, but I was able to improve this greatly using all the performance tips found all over the net. In short: install Native JAI, tune jvm, enable gwc. But still.
In my search for performance tips, I stumbled accross the following results: http://www.slideshare.net/gatewaygeomatics.com/wms-performance-shootout-2011
In this slideshow is shown that MapServer on linux is considerably faster than Mapserver on windows. I tried to look for a similar results or benchmark for Geoserver, but did not find it.
Aside of that I also wonder if the container has any impact on the performance of GeoServer (e.g. jetty/tomcat/jboss/...).