Rule of thumb:
1. Use the mesh generator which is being used by your friends who are available to help you out.
2.Best sotware in market is ICEM (Hexa), but it is difficult to learn and takes alot time in mastering. Its tetra + prism version is very efficient and easy to use.
3. Ansys meshing is new technology and very easy to use.
4. Gambit is very easy to learn and its tetra with boundary layer (in 3d implementing boundary layer often...