I like that it can simulate complex flow fields for free-stream turbulence analysis (i.e.: wind tunnel test). It also has excellent visualisation capabilities with user friendly interface which allowed me do perform several tests in less time than my colleague had done before using AutoCAD or MATLAB! Free stream is not very easy to use so you need an expert knowledge about this program but if your are good at math then there's no problem doing all kinds of calculations regarding aerodynamics problems. We used mantiumflow as our main tool when modeling airflow around aircraft wings; we were able solve many different issues such us vortex shedding frequency estimation, pressure losses due to boundary layer effects etc.. There was nothing really dislikeable until now since i did other programs too recently.