I don't have any visibility on the ROI.

Our service statistics aren't particularly impressive, but we have seen a return on investment.

I would rate it a five out of five.

It's an essential part of our infrastructure, and we'll keep using it.

The solution is stable.

It's complicated answer this question, but the ROI depends on Datacenter.

The ROI is absolutely linked to time. You can save a lot of time using Nagios monitoring because otherwise you need to check all of your services or system one by one.

No ROI was requested by my customer, only visibility by their management and using their knowledge on Core 3.

The ROI is very good.