Hi Jack!....hmm, should say that on an aviation forum.
I think you will find the ailerons are more responsive than compared to a wing with Dihedral. The way I think of it, because of the reduced lateral stability, a smaller control input will be enough to initiate the roll. Then, the instability will assist in maintaining the rolling motion. Think of the good ol' upside down sugar bowl with the marble on top example. Push the marble only a tiny little bit and away it goes!
With Dihedral, the aileron input and the lift its generating has to overpower the increased lateral stabilty while rolling the aircraft, if you get my meaning.
So, I would say that the aircraft is more responsive in roll with anhedral as opposed to being more controllable. Takes a bit more effort to stop them rolling once they get going.
Hope I haven't totally confused you.
Cheers,
Mister W