Speak for yourself. Programming in R is amazingly expressive for prototyping. Its semantics are extremely lispy, yet it provides excellent support for fast numerics. It keeps me focusing on the problems I want to solve and provides me the tools to abstract them quickly to handle related problems. Meanwhile, python keeps forcing me to care about pesky implementation details which I don't care about on a first or even second or third pass. I really can't understand people who like python over R. Did you guys not read SICP?