I'm honored that you would respond to my comment! I meant that in no way as a dig against Gensim. Really I'm referring more to the pythonic environment itself - the larger an NLP application grows within Python, the more overhead baggage it picks up (due to logic written in Python - plus Cython is far from a silver bullet). That is not to mention all the difficulties involved in parallelization within a Python environment.

For what it's worth, when I was at a large company recently, I did use Gensim too - I was originally referring more to the case where you take a prototype for an NLP application and ask "ok, how do we scale this across millions of users"