Any support for i18n? (For English-only speakers: Excel's translation to other languages goes as far as translating function names, thus rendering non-English Excel users' knowledge useless when confronted with an English Excel. E.g., IF(ROUND(A1)=1,B1,C1) in English Excel is JEŻELI(ZAOKR.DO.CAŁK(A1)=1,B1,C1) in Polish Excel -- yes, with all those funky non-ASCII letters.)
It's really easy to implement the easy parts of spreadsheets, getting the hard parts right is why Excel continues to dominate the space.