ANSYS. Because ANSYS user interface is very good by ANSYS 17 they improve algorithm for solving, so solving time is also very less so i suggest u go for ansys. for ANSYS readily many tutorial is also available in YouTube. try it.
Answered with a tutorial: https://grabcad.com/tutorials/which-software-is-better-for-computational-fluid-dynamics-ansys-or-nastran
yes ANSYS is good for doing CFD while comparing with NASTRAN
it depends on what kinds of the problem are. It is well known that CFX and Fluent are famous CFD software which is taken over by anasys, but it doesn't mean these two pieces of software can be almighty. If your simulation is about incompressible fluid, you can try Acusolve.