Who Uses Perfection Planetary Pegs (PPPs)?

Here is a selection of musicians who use PPPs:

Lynn Harrell
Lynn Harrell plays a 1721 Montagnana cello and also a 1673 Antonio Stradivarius cello that belonged to the late British cellist Jacqueline du Pré. 
From 1985-93 he held the International Chair for Cello Studies at the Royal Academy of Music in London and in 1993 he became Principal of the Royal Academy in London

Turtle Island String Quartet
“It must have been like this when Beethoven was taking Vienna by
storm – the exhilaration of seeing the future of classical music
unfold before your eyes and ears.” – St. Louis Post-Dispatch
Its name derived from creation mythology found in Native American Folklore, the Turtle Island Quartet, since its inception in 1985, has been a singular force in the creation of bold, new trends in chamber music for strings. Winner of the 2006 and most recently, the 2008 Grammy Award for Best Classical Crossover Album, Turtle Island fuses the classical quartet esthetic with contemporary American musical styles, and by devising a performance practice that honors both, the state of the art has inevitably been redefined. Cellist nonpareil Yo-Yo Ma has proclaimed TIQ to be “a unified voice that truly breaks new ground – authentic and passionate – a reflection of some of the most creative music-making today.”
http://turtleislandquartet.com/

Richard Green
Richard Greene, "one of the most innovative and influential fiddle players of all time," grew up in Los Angeles and studied classical music until his encounter with the pyrotechnic fiddling of Scotty Stoneman; from then on Richard was a fiddler. 

Renata Bratt
Cellist and clinician Renata Bratt (www.renatabratt.com) writes articles and has been interviewed about improvisation and fiddle styles for New Directions Cello Ink, Strings Magazine, ASTA, Jazziz and the Suzuki Music Association.

Julie Lyon Liebermann
Julie Liebermann is performing violinist,author and composer. Her books and videos are distributed by Hal Leonard, and her orchestra scores are published by Alfred Publishing.

Daryl Silbermann
Former Product Specialist for Orchestral Strings at the Yamaha Corporation of America. She has played and/or recorded with Guns and Roses, Depeche Mode, Al Stewart, Michael Sherwood, Larisa Stow, Darryl Purpose, Robert Morgan Fisher, E.B. Fraley, and many other singer-songwriters and bands.

Danny Seidenburg
Danny is a performer, composer, arranger, clinician and jazz educator of international stature. He has toured, performed and recorded with Steve Reich, the Village People, Liza Minelli, Tony Bennett, James Brown, Richie Havens, Led Zeppelin, Black Eyed Peas, Smokey Robinson, recorded with his own progressive rock group "Spy" for CBS Records, improvisational jazz-fusion with "Szobel" for Arista Records, and original music for Windham Hill.

Crystal Plohman
Director, Fiddling Program, Blair School of Music, Vanderbilt University

Planetary Pegs are fitted to instruments from notable violin makers. Here are some examples (Source: Knilling):

Paul Magenot 1925
Oliver & Bisch 1920
Piotr Staszel 1925
Jean Babtiste Vuillaume 1850
Johann Knilling 1773
John Juzek 1925
Antonio Stradivari