What does the software or service do well? I love the ability to assign users different levels/areas of access so that they can keep pages updated themselves and I'm not constantly updating something when someone emails me. This is an especially nice feature the bigger the pool of people who need to edit the page gets.
What does the software or service not do well? The Interface looks a little old-fashioned and can be a bit finicky, which is intimidating to less experienced users.
What do you wish you had known about the software or service before using? It might be nice to, as we've done, give users a little document with a crash course in basic HTML stuff and addressing some of the quirkier features of Joomla. This can greatly reduce the amount of support requests you get.