[Bruno]

Ham-Fisted is incremental, it's just in units of -3 instead of -1. It's asymmetrical to High Manual Dexterity because (like many disadvantages) it's priced assuming the people that take it don't expect to be hindered by it.

My experience of Ham-Fisted is that the reaction penalty is a regular problem, and the actual DX penalties are negligable - because I'm not taking it on characters that will ever attempt Sleight of Hand or Pickpocket or Lockpicking or Surgery.

Acquiring Ham-Fisted after-the-fact unwillingly is a different prospect, and that's where Ham-Fisted from equipment potentially becomes a more significant disad... except you get to pick your equipment and you can take it off.