Today I’ve been fighting again with how to get GetFeatureInfo working in my Geoserver, Apache, Tomcat environment. It’s pretty simple actually: One needs a proxy which I put in
Proxy code can be found in
OpenLayers-2.9/examples/proxy.cgi (Download the full package of OpenLayers and use it instead of the package that ships with Geoserver). Add all necessary hosts to allowedHosts list.
Don’t forget to set it executable:
sudo chmod +x /usr/lib/cgi-bin/proxy.cgi
OpenLayers.ProxyHost = "/cgi-bin/proxy.cgi?url=";
Geoserver and Mapserver are both quite powerful but their developers pursued different goals.
To make the choice easier for you (I hope), here comes a general feature comparison:
||both are good
||maybe a bit better 
||better, supports WFS-T 
||no WFS-T 
||Mapfile generation can be aided by QGIS, but not comparable to Geoserver’s web admin tool
||good for Java developers 
||PHP Mapscript, good for PHP developers 
||uses standardized SLDs
||powerful; styles are part of mapfile
||one WMS/WFS/WCS service for all users 
||a mapfile means a service 
||CQL and OGC filters
||embedded SQL statements
New benchmarking results should be available soon . Meanwhile, you might wanna watch last years results .