I like OpenOffice in
theory, but not in practice for what I use office applications for. It's awesome for basic word processing, spreadsheets and presentations, and has built-in PDF support, which is especially great on non-Mac operating systems. Not to mention, it's got the amazing perk of being free, and can open up Microsoft Office files without you actually having to pay MS for a licence.
However, OpenOffice's interface feels really clunky to me (not I'm too crazy about MS Office UIs, either—MS Office 2007 drove me insane when I had to use it on work Windows boxes), and I don't like the fact that Writer doesn't support advanced typography (ligatures, contextual alternates, oldstyle figures, etc), which Apple's text editors do. Microsoft has only just added these features into Office, at least in Office 2010. Not sure if they're adding them into 2011, but I hope they are. Microsoft included advanced OpenType features as a
Windows feature back in the mid-2000s, but didn't put them into the Office text rendering engine until this year. Kerning, as far as I know, has to be turned ON, rather than off, in MS Office, which makes some type render badly. That being said, Office has better support for advanced typography than OpenOffice, which as far as I know, cannot even
open .otf font files, which are very common for designers. Not too fond of its layout features, either.
As a graphic designer, I really need to have access to advanced typographical features, so OpenOffice isn't going to cut it. So, yeah, specialist needs can definitely make or break what applications and platforms you use, so I really can't blame anyone who has to use Windows (using that as an example) for mission-critical stuff. So, yeah, I'm just going to wait for MS Office 2011 to get released and buy it. I kind of see Microsoft products for the Mac as a 'necessary evil'—if I've got to use MS for something, I'll use their stuff.
I could be proved wrong, though, and might download the newest OpenOffice to see if things have changed. If they have, I'll write about it.