If you don't mind me asking, what will happen to these outlines once handed off to the Word or Excel users? Are they mostly just going to be edited, or are they going to be heavily added to or expanded on into a non-outline? And, are you expecting to bounce files back and forth between you using OmniOutliner and them using Word/Excel?
We do hope to offer more export options in the future, and a better Excel format is one of them. But, for right now, there isn't a good option for passing off formatted multicolumn data that can be nicely edited. CVS is available for moving non-formatted data to Excel.
If you come to the decision you're not able to make use of OmniOutliner, we do offer a 30-day return guarantee and hopefully we can improved OO to fit your needs in the future -
http://www.omnigroup.com/support/store/refunds/
Let me know if you have any additional questions.