I can't remember one single time when they did not post. Sometimes they even post the same day I check out.
BUT, for me at least, it's way too often incorrect amount of points and sometimes maybe just points post but not the stay/nights.
Now latest this week only supplement I paid for a junior suite posted and even that only for one night. Nightly base rates, the elite bonus, the welcome points and qualifying nights/stay did not post.
And what annoys me is that CS asks to fax the bill to them. I don't know about US and other developing countries, but where I live nobody has used fax for about 10 years now. But then again, some countries still use cheques as well...