OK, so M$Office 2010 is pretty good. I like the built-in integration with SkyDrive and other M$ web thingies, and otherwise, it just works. I do NOT like the still proprietary formats, and some of the eye candy and hand-holding is over the top, but if I had to I could live with those things.
OpenOffice 3.2.1, OTOH, just works. Oh, cool stuff to match OneNote isn’t a part of the mix, and if one actually needed the page layout capabilities of Publisher it’d be a tad of a stretch for OO Writer, but overall I feel more comfy with OpenOffice’s approach.
Personal taste. Oh, a few other nice things were in M$Office, but most folks won’t install the Office Professional Plus 2010 version of M$Office I did–which included some TechNet-only additions to Office most readers here won’t be concerned with–some back end–such as Sharepoint (Designer and Workspace) so a straight-up quick look at just the primary components–word processing, database, spreadsheet and presentation software–is all I’ve done so far.
One thing OO really has in its favor: I can use it on all my computers without any compatibility layer intruding. Linux, BSD, Windows: OO just doesn’t care, since it works natively on ’em all.