You may want to consider the Acratech Ultimate Ballhead. One of the lightest around, and uses the ArcaSwiss type clamps. Alternatively, the Really Right Stuff's BH-40. Both these alternatives are pro level QR clamp ballheads, compact and light.
Of course, there are the Korean and the Chinese ones that you could consider.
The softer all-rubber knobs will be easier on your fingers. I have the earlier version where only the main knob is rubberised. I would've preferred the clamp knob to rubberised, as it can be painful on the fingers when tightening the clamp.
The clamp with the detent pin is a 'safety' feature which will help to minimise the possibility of your camera/lens slipping off the clamp if it is not screwed on tight. Again, something optional. Up to you to decide if it's worth the US$10 or not.