I have had this out on GeoNet for about a month now. My issue is the 'Base simliarity on' section. I understand that it is currently only based on fields that are numerical, but I think that it could be used far better if the tool could be filtered by all of the data provided. In my case, the majority of my fields are text based due to either leading zeroes or the actual entry being text characters such as 'GG' for 'Good Golf' view. My post in GeoNet can be seen at: https://geonet.esri.com/thread/175515
I will be at the UC this summer and will be at the help island to bring up the issue as well.