I object to excel for quantitative analysis on the grounds that it is impossible to demonstrate anything that might give one confidence in an analysis. There's no record of the steps taken to transform data. By contrast, in R, you can start all the way at the beginning and trace everything that is done to your data, right up to your final answers. You can explore the data without wondering if you've accidentally performed the Sort of Ulimate Corruption.
It's like algebra class: no credit unless you show your work. And in excel, there really isn't a good way to show your work.