The FAST system, like the Brother 1034D (I also have one!) is where parts of the looper threading path are simplified by having a lever to slide to assist, rather than having to use tweezers and needing triple jointed fingers and eyeballs that see round corners!
Automatic systems are like the babylock air jet threading, where you poke the thread into the air jet and it caries it through the path automagically. Not sure how it works, but it's certainly magic! AND expensive... And since I don't find threading most sergers difficult, I've never seen the point of wasting the readies on such a thing.
The 1034D is very easy to thread. Follow the diagrams and it takes about a minute to do all 4 threads from scratch. You can also tie-on and pull through for a quick change... Use reef knots, zero the tension, and clear the needle threads from the lower looper, and just pull through. On anything bigger than a size 70 needle, I can usually get the knots through the eyes of the needles as well!