Found this on another forum, here is a "review" of it at the following link: https://www.youtube.com/watch?v=yhNnpXYvg40 (I am unable to embed it for some reason). Here is a quick summary of it: "HerdProtect is a second line of defense malware scanning platform powered by 68 anti-malware engines in the cloud. Since no single anti-malware program is perfect 100% of the time, HerdProtect utilizes a herd of multiple engines to guarantee the widest coverage and the earliest possible detection. As a second line of defense anti-malware solution, HerdProtect is designed to run with any existing anti-virus program already installed on a user's PC. HerdProtect is a free service to help user's find and remove malicious software."
There's an exisitng thread about it here: https://www.wilderssecurity.com/threads/herdprotect-vt-hmp-cross-over.357311/
I think the hitmanpro approach is better by allowing multiple AVs but keeping the list to a short but reputable few. To scan your system with "68 anti-malware engines" is going to throw up a ton of false positives.
I used to use it for a long time but too many FPs and they create cache files, just thousands of cache files. Not exactly suitable for me.