I assume you know about the 'apachectl' command, which you can use, amongst other things, to verify the syntax of your config files (apachectl configtest)
The 'status' and 'fullstatus' options will also tell you exactly what the server is doing if it seems to be slow or is refusing connections. There's a directive for that as well so you can view the same thing on the web: http://httpd.apache.org/docs/2.0/mod/mod_status.html
Like James says, it's a pain that CentOS do it differently - but the main thing you need to remember is that CentOS use 'httpd' instead of 'apache' for all the directories and commands. I've come across other people's servers where both seem to have been installed (not sure how) which gets *very* confusing...
Four reasons I stick with Debian:
(b) it's nice and reliable, they always delay the latest version if they need to fix bugs / improve stability
(c) it has many more packages than CentOS - about 22,000 compared to 10,000.
(d) ease of upgrading