I used to play a bit with Solidworks 2015 several years ago, however, my experience with the program is very little. I’m a full-time Rhino guy. The fillets produced by Solidworks are often off the file tolerance, because that program uses some under-the-hood cheating to do get the job done. This is evident once the models are being exported from Solidworks to STEP or IGES file format. They may look fine inside Solidworks, but once they are imported in Rhino, there are plenty of gaps around the fillets.
Unlike many other Rhino users, I’m almost satisfied by Rhino’s fillet capabilities, except for some annoying drawbacks, such like the inability to automatically trim the ! _FilletSrf to where it reaches the end of the shorter target surface. Recently, I created a dedicated topic about that request:
Currently, the ! _FilletSrf command will automatically extend both ends of the fillet, but this is rarely useful due to the weird extensions that go in some random directions that are not usable. That alone forces the user to trim each fillet surface by two isocurves extracted subsequently.
To make the things worse, by default the ! _ExtractIsoCurve command is programmed to create longitudinal isocurve (along the U direction) instead of a transverse one (along the V direction). I found one of my post where I reported that inconsistent behaviour:
Hopefully this will be fixed in the future. 