[Techtalk] Experiences with Nagios and/or Advanced Host Monitor?

[Tracey]

I have inherited some servers in a cloud space that had no monitoring
set up. They are running Fedora Core 8, and will be upgraded to FC11.

I had been reading up on Nagios. Another server admin here said he had
issues with Nagios being buggy & had better experiences with Advanced
Network Monitor. Do any of you have experience with any of these, good
or bad? Are there other monitoring tools you prefer?

Thanks,
Tracey