The pros were that the midrange was made a little more even, the bass was fuller and tighter, and the treble was a little smoother. The cons (to me anyway) was that it increased the output just a little too much and made the pickup too hot, and even though the mids were more even overall, they were a little too aggressive and tended to fatigue the ears after a little bit. Some people like that incarnation of the JB, some don't. I can see the reasons for both.
Those clips were done with a 500k pot, I thought it sounded a little better with a 250k, personally - less strident in the upper mids. I'd recommend giving it a try at the least.