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.
Thanks! I tried Open Office several years ago. Tried in the most basic sense - I managed to get the programs downloaded, but I could never get the spreadsheet program to work - no formulas would work, help wouldn’t work, so I gave up. Maybe it’s time for a new try.