I haven't used it for programming languages (though I intend to the next time I learn one), but I used it for my maths degree (for sit-down exam at the end of t

I haven't used it for programming languages (though I intend to the next time I learn one), but I used it for my maths degree (for sit-down exam at the end of the year), and it seemed to be very effective. The danger is always that it can be time consuming to create the content for it. Anki does look a bit raw, but worked absolutely fine for me (though transferring LaTeX-ed decks between devices was a hassle). There's also memrise.com, which mostly focuses on languages, but allows users to create content on any subject. It's also more easily shareable there, I think. In any case, the science behind SRSs is good, and in my experience it helps a lot with memorisation!