But...I think one thing gets overlooked way too often. For "data scientists" or "statisticians" or [insert new term here], the majority our non-modeling time is spent on just plain old data wrangling. To me, R is unbeatable here. I've tried Python ~2 years ago and pre-1.0 Julia.
Using tidyverse you can do pretty much anything to any dataset, often *without a monstrous amount of keystrokes*. (The pipe syntax is awesome). If you really need speed you can always switch over to data.table for uglier but faster code. I really tried but I could never replicate the "brain cycles to keystrokes" speed of R in Python/Julia. That is, being able to intuitively and quickly just convert my thoughts into readable data wrangling code.
Sure the base R language is not that "fast" and Julia/Python benchmarks are way faster. But in practice this doesn't matter to me. Most of the performance sensitive packages are written in C/C++/Fortran anyway (rstan, brms, glmnet, caret). I don't care that I could write 3x faster loops. The extra 5 seconds for that one piece of code doesn't make up for the absence of a good data wrangling ecosystem.
My message to the Julia team: You can get a very large portion of the R userbase to switch over if you focus on a Julia version of the tidyverse (especially dplyr). I know that DataFrames.jl exists but it just doesn't even come close. There's a difference between "you can do this in Julia too" and "here's a clean/intuitive way to do this better without extra baggage".
I'm sorry if the above seems harsh. I genuinely appreciate the Julia team's efforts. I can only imagine how hard it is to create a new language. I just wanted to be honest.