[xerula]

I would say it depends on precisely what scientific work you need to do. E.g. for phylogenetic statistics there are some nice R packages that bundle simulation techniques and measures that are so far not implemented as conveniently, or at all, in Python. So you need to explore what packages/libraries are out there that fulfill your needs (and also consider how much time/skill/interest you have to code your own packages/libraries where needed). R is still really popular for stats/prototyping/data viz and a useful language to have up your sleeve.