Well, I'm not sure about Hebrew, but I do know that i'm pretty disillusioned with Word. I take Latin and I need only one, fairly simple accent. It is a macron. It goes on vowels. It is just a straight line. A dash above the letter. Very basic. It's used in editing, too, and in pronunciation keys. That is to say this: it is not for use only for Latin, nor is it totally unheard of. Word, however, despite being huge, doesn't have macrons. More than that, you can't GET them for Word, because Word doesn't support unicode. This is pretty worthless. For such a huge, expansive program to be so limited in scope is pretty absurd. So, like I say, I'm not sure about Hebrew, but be wary; just because Word is enormous doesn't at all mean that it is necessarily capable of doing what you need.
Now the alternative I've started using, though I doubt it will help your case much, is OpenOffice, which is both free AND very good. It's comprehensive, comparable to Word, and does what I need much much better. And did I mention free? There's also NeoOffice, which is another version of OpenOffice that I need to try soon. So give those a shot if you want. I doubt they do Hebrew right off the bat, but it's probably very likely that you can get such a package for it. And besides, they're free, so even if they don't have what you want, you'll have lost nothing.
Anyway, my advice is to just be wary of Word. Don't buy it unless you KNOW it can do everything you want.