Let's take the stand of the *nix crowd to start with. What do they have to say about Word? Well, the first thing they say is that it is bloated, thereby meaning slow, too feature packed and so on. May very well be. There are many features in Word that you don't need; granted. Furthermore, they dislike the "point and click style" of Word. Next, it is bad that it is proprietary. And worst of all, the support for equations and references is meager.
Now, we take the stand of the Windows/Word crowd and listen to what they say... LaTeX feels so old-fashioned. It is only for techies. I don't want to write code to write down what I am thinking. The syntax can be bewildering. I
t is hard to install. I cannot send my documents to others, who are most likely using Word anyway. Word is easier.
Now, I am a *nix user and a Windows user. Both the stands described above are wrong. LaTeX has a pretty steep learning curve, but it is not difficult to use or set up. If you don't like writing code or markup, that is a personal thing that is only up to you. On the other side, you can use Word effectively without any clicking at all - there are shortcuts for everything. Macros let you make shortcuts to very complicated things. And support for equations and references is great if you are willing to use third-party software (MathType and EndNote being the most common). If you are on your own budget, the price might be stiff, though.... ($300 for EndNote alone...).
So... why don't we just let people use the tools they like and put the discussion to an end? That would be a relief... :-)
That being said - after trying a gadzillion solutions - I think Word is the most efficient way to write for me, because I use a lot of the features making up the "bloat" of the software :-)