I think once you get good with it just typing latex is much faster than selecting symbols from a palette using the mouse.
I agree. Also, the quality of typesetting produced by TeX is excellent. I am not familiar with the current state of the equation editor in Word, but I would be surprised if it is close to it. However, learning LaTeX requires an effort. The upshot is that if you are going to type math texts professionally, LaTeX is much preferred. If you are going to do this only occasionally and in limited quantities, then Word will do. Concerning the forum, the subset of LaTeX that is sufficient here is rather small (50% of what you need can probably be learned in 10 minutes), and the increase in the quality of posts is great, so it's worth the effort.