Going thru the CAM selection too atm.
Have SolidWorks, about to purchase SolidCam.
If you already have SolidWorks, then you are on the right track of getting a CAM system that is an addin to SolidWorks - allowing you to work directly on the CAD model without export/import/file tracking issues.
My research has lead me to choose SolidCam:
1) Have used CamWorks (way too many hours) - not a user friendly product.
2) BobCam - its cheap for a reason.....
Mastercam has always been a premium CAM product, but times are changing and Mastercam is not keeping up. Working with solid-models directly in Solidworks is the way to go, while Mastercam does offer a SolidWorks addin option - it won't be as functional as Mastercam on its own.
I have found that no functionality will be "missed out" by going with SolidCam over MasterCam.
SolidCam is just as pricey as MasterCam, but its not worth skimping on technology that is driving the cnc-machines.
Note that my choice is not made easy - my company already has a module of MasterCam X5 (worth many thousands), which we are prepared to dump for change to SolidCam (doesn't help that MC support in Australia is s#%t poor).
Sorry no comments on HSMworks - haven't looked at this option.
Hope this helps! A great CAM system is an invaluable asset to a CNC company!