Which do you use for your forum/forums? http://www.litespeedtech.com/litespeed-vs-apache.html I use litespeed, I came from apache, I think that litespeed is a tonne better.
I'm honestly still running Apache, as it serves it's purpose and can't say that I've EVER noticed a difference between the two
I've used it and it certainly makes a difference. I do run customized MySQL, Apache & Kernel installation.
Litespeed for high concurrency based traffic sites and my reason why (take out the caching comparisons) http://vbtechsupport.com/33/ Step above Apache and just below Litespeed, would Nginx for everything else.