The InTact Technology has been on the Palm and WM versions for a while now, it just keeps all formatting intact. It works very well.
Personally, Docs to Go has been on every Palm or WM device I have ever owned (a lot), it is a great piece of software. eOffice has always seemed really slow to me and difficult to use.
Right now I use Simprit's GridMagic for Excel spreadsheets and have been very pleased with it. I noticed that just yesterday the opened up a "community" version for free. Maybe that is a good place to start until Docs to Go arrives in a few months.
GridMagic for BlackBerry - Excel Compatible BlackBerry Spreadsheet