When evaluating Vulnerability Management, what aspect do you think is the most important to look for?

Ensure compatibility of the vulnerability software to the organization's needs.

- Great dashboard
- Reporting
- Supports multiple formats (PDF, CSV, XML)
- Ease of management

0. Your company maturity (to receive a excellent tool or if it can be a less commercial one) VERSUS speed to correct problems encountered;
2. TCO and user-friendly (of operation, installation, training and maintenance);
3. Ability to integrate/export to other platforms (ETL, OpenAPIs, formats & standards - i hate consoles!);
4. Type of licensing and pricing (per year, per asset, per module...)
5. Supplier reputation

Zero is the most important. There is no advantage/gain in having an excellent tool (with a high annual cost) if you are not prepared to handle its output. Start small and grow (and maturity is the trigger for change your tools for one better).

Today, with a wide variety of presentation plataforms (xLAP tools like a PowerBI, QlikView, OBIEE, Tableau, Pentaho etc) the quality of dashboards is secondary. 

Agent-based system but able to correlate agent discoverer hosts with network scanning (avoiding duplicates)

Comprehensive and documented APIs so you can download data and orchestrate the platform as needed. 

Reporting portal with capabilities similar to PowerBI, Splunk, or Elastic Stack. 

A great product team that does not a tunnel vision (i.e. we know what is right) and is willing to listen and learn from experts, customers and partners

It should support any or all platform, depends on where you will need to use it.
- OS (Linux, Windows)
- DB (Oracle, MS SQL, DB2, etc.)
- Cloud (Azure, AWS, Google)