I have an older serger but I love it!!!! When I went to learn how to use it I made my own directions and used colored pens to make a diagram that I could see and understand for threading.
If money was no object I would get a self threading and with automatic tension control. Of course, I'd shop around and see which one fit my budget and me. A used one from a good dealer would be OK too. All the major brands have them now.