Can one go between Open Office and Office 2007? That is, to say, are the files compatible?
For the most part, yes. The biggest issue I've noted is that things sometimes tend to lay out differently in Word/Swriter documents -- a big problem for desktop publishing, where layout is crucial, but not so much of a big deal for memos, letters, etc.
I have three personal computers -- an iMac, a Fedora desktop (that I post this from), and a Windows XP laptop. I use OpenOffice, GIMP, and Firefox on all three, which gives me a pretty seamless experience with the most common applications. I sync documents using Dropbox, which makes working on something a lot easier when I'm bouncing from location to location, working on different machines.
In my limited experience, yes.
Funny story: I recently built a new computer and had heard Open Office was getting competitive to Office, so I installed in instead. Turns out it lacks a few features critical to me (niche things that probably wouldn't bother most people), and I ended up going back to Office 2003, which I've never liked, without deleting Open Office. So eventually, I decided to upgrade back to Office '97. I liked it so much better than 2003 that I actually bought it again cause I couldn't find my old ones. So someone sends me a .docx document (Word 2007 format) and I open it and it Opens in Open Office, because I never uninstalled it and .docx doesn't associate with Word '97! so now I have the best of both worlds, I have the version of Office I like and provides the features I need to work on my stuff, and Open Office as a file viewer/editor for newer formats '97 won't do! (Office '97 -- the best Office yet!)
Yes completely...pretty neat huh?