Well, I'm just going to dive right in here first to break the water...
I don't see the "other" option, and that is what I choose when I fix.
I will burnish, then occasionally I will steam a painting as the fibers of the substrate will grasp and hold the pastel particles.
By burnish, I mean I will put a sheet of glassine over the painting and press the pastel .
For steaming, I have a portable travel steamer that I like that I will lightly pass over the pastel. I won't get the pastel wet, but I put enough steam where the color will look like it has changed - darkened. Then when it dries I really don't see much of a difference. After steaming, and after it has dried, only a small amount of pastel will be released on my finger where I test it.
I have a few cans of fixative around that I will use on occasion, but I hesitate using the canned fixatives because of the vapors.
I hope to buy some spectrafix some day, but when I have the few extra dollars, it usually goes to buying pastels, or paper.
Some people say that steaming changes the molecular crystalline structure of the pastel. Maybe it does, but I don't notice it with the naked eye.
Here is a thread I started a few months ago about steaming.
I'm interested in what everyone says too.