I am not personally a developer but being an SEO am able to work with most CMS platforms pretty well.
Wordpress for me has been the winner for long time. I have had clients who have used Joomla and it has been a complete nightmare for them. Doesn't help when developers disappear and leave you to try and find another designer at short notice and then find out nobody will touch it with a barge pole!!
Same goes for any kind of bespoke system. What happens when the developers are no longer around??
So word of warning. Make sure that whichever platform you go with, that is well supported and that there are others on standby if the developers are no longer around to support you.