Question about MS Word alternatives

I am contemplating buying a netbook, mainly to access the internet when I'm travelling, but I also have delusions of doing work on it while travelling. Most of the ones I'm looking at don't have CD/DVD drives on them, which means I don't have a mechanism for uploading work-supplied probably not-licensed-for-home-use Word on them, and it's not preloaded on any of the ones I've looked at.

So my question is for people using Open Office/ Google docs/ other free wordprocessing programs that are downloadable: how compatible are they with Word? Because if part of the point of this is to do work-related writing while travelling, I need something that easily transfers Word docs to the freeware and vice-versa without too much annoying loss-of-formatting, etc, since there's no way I can switch to Open Office on my work computer. Anyone have experience with this? Suggestions?