We have 40+ sites in 20+ countries. We use egress filtering and force most users through proxy servers via WPAD.
WPAD is great and works 99.9% for us. However, we have had a few cases where WPAD support issues has caused browsers (only MSIE - on rare occasions) or 3rd party apps (WebEX voip) to fail to work as they do not correctly figure out where the local proxy is - try direct - and fail.
So are there any other mechanisms for enabling enterprises with a plethora of egress points/proxies to be able to support all browsers (ie not just MSIE) and other web-clients - besides WPAD? As I mentioned, WPAD actually works 99.9% for us, but the trouble with that situation is that people only "see" the failures - and grizzling begins...
PS: no, "use DHCP" is not a different option. That is merely an alternative mechanism to deliver WPAD (the primary being DNS). Just thought I'd answer that before someone else does ;-)