We use excel exclusively at our business and have tried Google Docs, but they have been so slow and break so often that we basically took the model we have been

We use excel exclusively at our business and have tried Google Docs, but they have been so slow and break so often that we basically took the model we have been using online back into excel! Google Docs scripts are cool but far too often they break. In the interest of speed, what are you going to keep vs. trash out of the excel functions kit? I bet you could get an incredible tool by keeping top 30-40% of functionality, because lets be honest, anything beyond that an back to Excel it is...