None of the custom weapons (which includes nunchuku, sai, fans, wheels, etc) work with any weapon feat. So no weapon finesse (which is the one that really hurts most monks), no flurry of blows, no weapon focus, no improved critical, etc..
I know it's rather disappointing, but for whatever reason the custom weapons have issues...
(the too slow typing edit): And yes, what the above people say is correct; kamas work with monk attack bonuses, but don't get the damage bonus or work with the "punching" type feats.
(the further edit because re-read the original post edit): Also, gloves that give attack bonuses (lion, malar, dire bear)are the same as weapons for overcoming damage reductions, if that is what you are worried about. Although they don't give the damage bonus that the +x weapons do, they can be used at lower levels than the equivalent counterparts, which is a nice little advantage.