iWork 08 does format things slightly differently perhaps from Office, but when you go to export, it should eliminate any of those problems.
Also, contrary to what someone else said, you can edit .Docs, it doesn't need to be converted or anything like that first. And you should be able to open up OpenOffice or Office07 files natively without the need for a converter, I mean shoot Leopard's TextEdit can save to .docx and .odt, so why wouldn't iWork 08 be able to open them? At least that is my opinion.
Honestly, for the price difference between Office and iWork, the minor issues like having to export to .doc instead of directly saving it to that format or any slight formatting issues can be overlooked. And if you are always directly printing your files, then there is nothing to worry about, and the nicer layout features of Pages might just impress your professors, and I know that Keynote will really impress them, and Keynote can save to .ppt, .mov, html files, youtube even.