Excel on Pocket PC

I understand that some complex spreadsheets transferred
from PC to Pocket PC will not function since some of the
commands are not recognised. However, similar complex
spreadsheets seem to function properly on Palm OS (Sheet
to Go). It seems a bit strange that Microsoft cannot
produce a fully compatible spreadsheet between PC and
Pocket PC when Palm are able to.

Any suggestions on how it can effectively transfer complex
excel sheets from PC to Pocket PC? Otherwise may have to
think about getting a Palm instead.