At SCP Science, we produce industrial microwave heating systems. We have been using HFWorks since 2012 to design  antennas for microwave heating, RF traps, couplers for our reflectometers, and coaxial-waveguide transitions. Most of these designs were fabricated and the measurement results closely match the simulation results obtained from HFWorks. Being fully embedded inside SolidWorks, HFWorks has given us a distinct advantage. We did not need to export the assemblies to create drawings needed for the machine shop.
We have been using the Antenna and the S-Parameter features of the software. We are particularly pleased with the speed of the fast sweep. We also found the technical support provided by EMWorks prompt and professional.