I have several complex spreadsheets that work perfectly in MS Excel, both the Win32 and OSX versions, but that generate dozens of errors or simply won't work in Open Office and NeoOfficeJ. For one thing, the "rate" function is not interpreted correctly, meaning that most any spreadsheet that deals with financial data or forecasting will need to be rewritten. Most macros just don't run at all if attached to a drawing object like a 3-D button. Also, formulas that refer to values that are stored in a drop down list take forever to calculate, at least in really large spreadsheets. The same fields update almost instantaneously in MS Excel. Still, considering the cost differential, this is quite a bargain. I just wish they would improve the cross-compatibility with MS Excel so that I could actually use NeoOfficeJ with my existing spreadsheets.