I've been using kdb+/q for a long time (7 years now) - and can attest to its speed. Objects are placed in memory with the intention that you will run vectorized operations over them. So both the memory-model and the language are designed to work together.

Lots of people complain about the conciseness of the language and that it is "write-once" code. I tend to disagree. While it might take a while to understand code you didn't write (or even code you wrote a while ago), focusing on writing in q rather than the terser k can improve readability tremendously.

My only wish is that someone would write a free/open-source 64-bit interpreter for q - with similar performance and speed to the closed version. Kona (for k) gets close https://github.com/kevinlawler/kona