I've used Mathematica, R, and Python extensively, and even Matlab (cringe). I reach for Mathematica when I need to do something symbolic (algebra, derivatives,

I've used Mathematica, R, and Python extensively, and even Matlab (cringe). I reach for Mathematica when I need to do something symbolic (algebra, derivatives, etc.), and also for the built in graphics. It is easy to interactively build up plots that give good insight into my data. It also is easy to problematically create quite complex plots. It is enough better at that that I don't just stick with R or python. I can get it done faster in Mma, and the plots also look nicer. The distribution (random number) functions are also very nice, which I often use hand in hand with the histogram, when I want to play around with statistics. Edit: The graphics also scale better for largish data sets. If I want to plot a few hundred thousand data points, Mma feels a lot faster.