I've worked with one organization that uses Excel sheets to model product mathematics for gaming (gambling) equipment. They won't even use the Macintosh version of Excel since they can't be sure the math will come out exactly the same as the PC version, and the PC version is what has gotten them approved by the gaming boards before.
Call it superstitious, but they don't have the time or expense to sit there and prove that another spreadsheet works 100.00% identally to PC Excel. So now they run Excel in VMWare on OSX. There's irony there, but what can you do?
Most people I know who sit in Excel all day use Windows Excel on a Mac. OS X is a better platform (it's nice to have the terminal right there) but Mac Excel is trash, and Microsoft knows it.
Call it superstitious, but they don't have the time or expense to sit there and prove that another spreadsheet works 100.00% identally to PC Excel. So now they run Excel in VMWare on OSX. There's irony there, but what can you do?