Wordpress has the most features and overall support, but does require that you are somewhat religious about upgrading, especially when the upgrade is addressing security issues. Leaving a blog in an old version is an invitation to hackers to fuck with your sites/server.

With that said, there are programs now that you can install to monitor and upgrade your sites and plugins from one control panel. Check this article for at least 8 WP Management Systems ... some of which are free.