At the company I work at, we only have a limited number of Microsoft Office licenses for those higher up in the company, and we don't have the money to buy more. All machines have OpenOffice.org on, and I can't spend an entire day at work without someone complaining that they hate OOo and want MS Office. Usually their reasons are unjustified (quote: "OpenOffice is just shit") but sometimes I get a serious reason (recently, it's rendering and creation of graphs and charts and the creation of complex formula) has been described as terrible.
So, in short, people hate OpenOffice.org whether they have justified reasons or not. Microsoft don't really need to worry, but if they lowered prices, those who deploy OpenOffice.org across the company may reconsider their options.
(also bringing back the pre-2007 menus as an option would be nice as I've had a huge number of complaints about that)