I've written something like 16,149 words for NaNo so far this year as of about two hours ago (and I've not written anything since I last checked it). Which puts me about five hundred and 18 words behind target. And coincidentally I managed to wipe a file earlier on my acer and lose pretty much five hundred words.
It also took me about half an hour earlier to run a spell check on the damn thing and so it's pretty much guaranteed typo free and all people and place names have capital letters as appropriate (apart from what I wrote tonight). I turned most of the grammer rules onto ignore, however - couldn't be doing with that. I did notice that it thought lot of my sentences were "long" and it queried the "wordiness" of somethings. However that being the basic point of NaNoWriMo I hit ignore and moved on.
Oh and I've not used it for a few days but Write or Die is so saving me this time round. I love it.