Well if you are using Wordpress...Don't go near Joomla :P Its totaly confusing.
I tried it, and then uninstalled it. I was looking for an optional way to build sites. For me, it was easier to simply build a site from scratch than to figure it out that control panel. Very comfy doing my own CMS stuff because good with DB's. I'm a big fan of WP for building a site or blog on the fly.
It is extremely customizable, it is definitely worth a try.
Used it, loved it, hated it
You can do amazing things in Joomla but it definitly has a steep learning curve compared with Wordpress.
It can be very confusing at first.
I've pretty much tried all the major CMS systems - wordpress is the easiest my favourite at the moment is Expression Engine - which is somewhere between the two (Wordpress and Joomla)
As Homer Simpson would say. "Joomla, is there anything it can't do."
Yes multiple editor accounts with defined roles - big ommision.
Used it in the past and it's quite frankly amazing, may be not easy for the first hand user but you learn quickly & easily!
No experience with it. I've always stuck with WordPress.
I've used it once but I prefer wordpress :)