Both Soul2Match and Find Your FaceMate are SCAMS, HOAXES.Use the same pair of photos and you will receive different results in both matching proposals as I proved in this blog.
Although Soul2Match's and Find Your FaceMate's personality similarity approach are correct, how they assess personality (indirect method to measure the Big5 traits, ADDS DISTORTION to the measurement) and how Soul2Match and Find Your FaceMate calculate similarity (low precision method, I guess similarity is calculated using Pearson's product moment coefficient) is incorrect.
Compatibility is expressed only as a percentage, from 0% to 100%.
Soul2Match and Find Your FaceMate suffer from the range convergence phenomenon I had discovered during 2003. That range convergence phenomenon is what I had called "the online dating sound barrier"
Who independently validated and independently certified how that profiling technology correlates with the Big5 traits?
I want to see a paper showing Soul2Match/Find Your FaceMate correlates with the Big5 traits (like the one for the Dewey Color System showing its correlation with the 16PF and the distortion it adds.)
ALL indirect methods, ADD a lot of DISTORTION to the measurement.
The best way to assess personality of daters is using a normative instrument.