save your money
I've used Excel since the 80s, and through 2003 it was good. This version is horrible. The toolbars are unintuitive, the charting (never that great) is less flexible (or at least more confusing). It might be OK for new users, but it's a waste of time to relearn everything for existing users, and there's no productivity benefit. Ugh. Avoid upgrading at all costs.