Hi Jorge. I've worked in naiad but for now houdini suits all my fluid needs :) Naiad and houdini uses the same FLIP solver, so i wouldn't say that one or another is faster or slower. Simulation speed is very comparable but the key is in flexibility of usage. In houdini you can work on every aspect of project you are working on. From sim to rendering and comping and that is the biggest advantage of working in H. It all depends on the user :) Hopefully that answers your question.