How reliable is the structural analysis results from solid works FEA tool. How will you compare it with other dedicated softwares like ANSYS?

I have experience of using structural mechanics module both in Solidworks and Ansys Workbench. As far as solidworks is concerned, it is really god for CAD modelling. In recent years, they have introduced some simulation packages as well, but I didn't find them much user friendly and reliable while comparing results from Ansys Workbench. The best one can do is, make CAD model in solidworks, export to Ansys Workbench in 'stl' format, mesh it there and perform structural analysis there. I hope this answers your question.

FEA in Solidworks is with the collaboration of Ansys. Its very limited options. Its helpful for doing basic Analysis.

Limitation:

Supports only Static cases.

Dont support Analysis on Assembly

Meshing is automatic and Tet.

Advantages with Ansys

Dedicated software for Structural, Thermal, Electromagnetic etc.

Very powerful Meshing options: hex mash.

Loads can be applied on particular nodes too.

In general we cant compare FEM in Solidworks with that  of Ansys. Its just of a drop from an Ocean.