Yes - I would be absolutely lost without mine. One of the best buys I ever made 3D-wise... navigation in Cinema 500% better with one of those under your left hand...
I have the older Space Explorer variant with the 16 buttons, which I have mapped to:
undo / redo
esc, shift, ctrl, alt
Component Mode
Last tool
SDS on / off (via Q)
Move, scale, rotate tools
CBR