When acting as admin for a farm of web servers one cannot avoid coming to know Apache like a close friend and sometimes foe. Having become well versed in version 1.3 I found the transition to 2.0 and 2.2 most recently to be straight forward for my tasks.
Performance tuning is an art form and takes some time to get your arms around; akin to juggling chainsaws. Apache has many more options than most pieces of software. There are also many more outside factors like load balancing and fail-over systems.
I have a lot of experience using mod_rewrite and compiling custom binaries of Apache.