The  most valuable features I found include :

The ability to add a vulnerability report

Support for STIX and TAXII

Threat Feed Manager- While viewing X-Force reports, users can  enrich IP, URL and malware reports using threat intelligence

So suppose you're investigating an a possible threat and you just found that there is an offense that is saying, one of your users had  access to some honey port defined address  You can quickly leverage X-Force to help you by doing  an X-Force exchange look-up quickly. 

 If you have an aspect of interest, such as an email, file , vulnerability data for, you can leverage X-Force to understand this in-depth.

The most valuable feature is you have the expertise of human experience directly involved. There is a team of experts.

It has a lot more AI capability in terms of trying to understand the nature of threats and detect some of those major threats.