I am an amateur J-er, but I can't stop jumping back to it and implementing something quick or re-implementing something I've done in another language. I am always surprised by how quick it is to prototype. I want to learn more how to use Qt to add GUIs to my projects, since unfortunately, only old-timers like myself like command lines. It doesn't get any buzz unless it has a nicely-designed GUI. Have you checked out JD? You can get an evaluation, non-commercial key to play with it. It should complement your kdb+/q background.