Dear Sir:
If you are referring to the John Williams of Pittsburgh, PA
Playing out of Breakers in Pittsburgh - Paul Mottey's Room - I can say that John is held in high regards in the room and with the Mottey's. I do believe he worked in Mottey's original shop with Jimmy White but do not have any direct knowledge of that fact. My understanding is that Jimmy acquired a lot of the equipment from the shop as did John when it closed. Details as far as who acquire what I do not know.
A couple of friends of mine (also collectors) have ordered cues from John. And I also believe he handles all the maintenance and repairs for the room.
I personally can not speak of the quality of his cues as I do not own one, but I can say the shaft he made for me is outstanding in my opinion. A dear friend of mine that got me into the game walked away and passed down an early 80's Joss gold-letter sneaky-pete. The butt of the cue was mint but my friend had whittled-down the original shaft to an amazing 11.5mm for playing bar-box 8-ball. I asked John to make me a new 13mm shaft.
The shaft John provided me in my opinion was outstanding, wood-to-wood joint with brass insert with (if I remember) an Aegis (sp?) ferrule and laminated tip. The wood grain on the shaft matches so well to the butt that when assembled all the grain aligns so closely that it appears it could be an original shaft if it wasn't for the lighter color.
I've had some say that is common with shaft replacements and just due to the natural grain of the wood, but I believe this is due to close attention and the proper "facing" of the joint by John. Especially with a wood-to-wood joint. I've had shafts made by Mottey's shop in the past but all those where with collars.
Sorry for my ramble, but as I said John is held in high regard at the room. Although a bit quirky at times (aren't we all??), John is a straight-up guy and I feel very meticulous about his work. I would concur with Mr Justis' assessment... extremely talented (bordering on genius).
I hope this helps.