Being able to customize it really speeds things up for me, and not just in SolidWorks. Having both monitors available, and photo's open, along with e-mail, it doesn't take long to get to where it's just not the same without the 3D controller.
I have several "generic" functions pgm'd into my space explorer that "cross-over" into other applications: escape, delete, Ctl., Enter, several more too. It's just, whatever you get used to doing.
Mine works very good when I'm sorting through the morning SPAM--- select the top e-mail, hold 'shift' with the 3d controller, use mouse to select last "junk item",then use programmed "DELETE" & "Enter" with the 3D controller. Never have to touch the keyboard.
Another thing I like is the way is will "scroll through" the feature tree. As long as you have your cursor over the tree area, 'pulling' or 'pushing' on the controller will scroll through a long list of parts - good for selecting planes, faces, or axis very quickly. No way I would be able to work as productive with only a keyboard and mouse, but then again, It's just what you get "used to."
Since our parts library is on a network, the first button I programmed on my controller was a "SAVE". Working along, and accidently hit 'save' every 4 or 5 minutes, really has eliminated some pain and suffering for me.