I'm looking for a new monitoring system and thought I'd ask the community which one is the best. I've had a look at Cacti, Nagios, icinga, opennms, zenoss... I'm looking for the one that is fast and easy to use. I want to give my clients the ability to login and see their traffic, disk space, cpu load, status of services like apache and mysql, and the ability to restart these services at will- and perhaps a nice integration with my favorite panel ISPConfig. any opinions?