Ive had the past couple years to play around with this wah now. It is extremely vocal with a nice even and smooth sweep. I wouldn't quite say it's the perfect wah for nailing hendrix tones- It can easily approximate them, but if you are looking for a straight voodoo child tone, a fulltone clyde or such may be more in store for you. I'd say it gets closer to any other wah I have heard at nailing curtis mayfield. In fact, I'd say funk is its forte.
My main amp is still my Sunn, with my main guitars alternating between the G&L Comanche and a Hamer Artist, and a G&L legacy and Hamer daytona on the side. The wah sounds incredible with each, without getting muddy with the hamer's humbuckers as some wahs are prone to. It responds quite nicely to gain, maintaining its sweep and vocal qualities very well up to fairly good levels of distortion/fuzz (again, if you wish to have a wah for extremely heavy tones, a wah specified and tweaked to those particular tones would be a better choice). It surprisingly does not squeal with any of my fuzzes - lovepedal balance/karl/dragon or pedalworx mcfuzz - until extremely high levels of fuzz.
also, the buzzing issue was actually not related to the wah, but with the lighting in the room. It has been taken care of and is no longer an issue.
Again, it is over 30 years old and I have not yet had a single issue with it. Battery life is quite good - I have only changed it a few times since I have gotten it.
The King Wah works nicely for rock, and even better for funk. I would not hesitate to suggest it to a friend or fellow guitarist, and would surely be interested in looking for a replacement should it ever be stolen.
For a vintage wah, it is quite a steal and without a doubt one of the most underrated pieces of gear I have seen