It is very easy for those who have never used it before since all of its functions are well illustrated in their user guide so there's no need to worry about getting lost or confused while using this application.
There isn't much I dislike other than that sometimes when you use some specific features like mesh refinement which require more time then usual but nothing too major at least not enough to make me quit my favorite app! As said above, everything is pretty straight forward with Mantium Flow including how to install it as well as the steps required after installation. The only downside would be if one has less computer power because of low RAM or processor speed they can experience lags during calculations especially when running multiple models simultaneously in parallel mode. If your looking into solving problems concerning heat transfer, flow modeling within structures such as pipes and channels etc., Mantiumflow.