Since I doubt that anyone is truly perfect I suspect that there would have to be at least one person who has had a bad experience. However my own experience has been far different and I have no problem letting him work on my own folders. As for any free advertisement, referrals on people who are in business to repair or sell cameras is part of what many of us turn to these forums to find. And "free" advertisement can certainly cut both ways as is evident by your own testimonial.
(with all due respect) blah!
spent alot of money with JK, many cameras, many services - lot's of mistakes, negligence, returns & waiting & waiting for a replies to emails.

camera CLA'd + new bellows & rangefinder calibration by Jurgen Kreckel - camera had to be returned to fix the rangefinder wheel which would not move the full range & was very stiff.

hair & debris inside lens elements (after claimed) thoroughly CLA'd camera purchased from Jurgen Kreckel (aka Certo6) - now removed after sending the camera back at my own expense & inconveniece - grrr!

532/16 returned from CLA with Jurgen Kreckel with (p)leather corner missing, dirt in viewfinder & unfixed frame spacing problem - so we had sent the camera back a second time for repair at our own expense - frame overlap problem was never fixed.

rare French Lumiclub circa 1954/55 back from repair with a very basic German shutter circa 1931 - was told by JK the original Lumiére shutter was unrepairable - but he was told by his shutter repairer that it actually just needed donor parts (which i had).
don't trust Jurgen Kreckel with any treasured camera's!
attn moderators why is there a testimonial here regarding a camera that this forum does not even cover?
says at the top of the page: 120 RF's 120 / 220 format rangefinders including Fuji, Koni-Omega, Mamiya Press, Linhof 6x7/6x9 cameras among others, but excluding the 120 folders and Mamiya 6/7 that have their own forums.
please move or delete.
best
alex