I've been using SALOME to create parametric 3D geometry. My use case is to parameterize my geometry features and export to STL files that I use with OpenFOAM. SALOME is integrated with a couple of grid generators, and I really like it's 2D/triangulation/STL integration with netgen. You can specify faces for refinement to a desired mesh size, so for example around complex features you can create a fine STL mesh and on simple shapes you can have a really coarse mesh.

I've found the 3D modeling to be pretty straightforward, and SALOME usually does a pretty good job if you have to go back and modify previous features (something I've struggled with in FreeCAD).

I've also used FreeCAD for mesh generation, and it works ok but I've found the triangulation leaves a lot to be desired for splitting up the mesh as needed for OpenFOAM boundaries.

If you're making STL files for 3D printing and you want a parametric CAD modeler for engineering parts, give it a try. If you want complex faces with artistic style, I would suggest Blender.