Fut Sao is a non-Yip Man lineage wing chun that comes directly from the Shaolin Temple. Those who have been fortunate enough to learn it are few. Fut Sao appears to have many similarities with Wing Chun in general but once you get past the surface you discover a vast amount of differences.
The 3 people that you see on the left are the nerve centers, as well as the gate keepers, of the system. These people have held, and passed down, this system in an almost pure form. From the founder to my own Sifu, those the lineage have gone through before reaching me have been only three people To my knowledge, no other style of wing chun can make that claim to my knowledge.
I am not going to try to do a piece by piece comparison of Fut Sao to the rest of the wing chun systems. It is not necessary. You can go to many wing chun schools, within the same lineage, and see the differences (even within the same lineage) for yourself.