We moved from Tivoli to Orion with one of the big advantages being no agents. The tivoli agent was not only expensive, but had to be tested with every upgrade, every install and every change taking a significant amount of engineer time. Using SNMP, WMI or a PERL script makes life MUCH easier because we do not require full testing every time someone sneezes.
The LEM currently requires agents and this was the biggest negative of the product when we evaluated it. The time and processes required to test this agent along with the change control nightmare makes me hate agents. But I do understand the advantages to the agent. We do have some systems that we will never get approved to add the agent, and that is where the option of agentless pulls are nessesary. Just like the discussion about SNMP, ICMP and WMI... the option to choose any of them or even multiple is always the best way to go.
