my experiences are much limited compare to yours. I dunno what to say but it seems like I have been very lucky so far with all my servicing experiences.
The only one time when I really have to return a service is from Journe. It was quite a long time ago. The watch came back to me with a missing screw on the case.
It was hilarious and the boutique was very nice to get that rectify. I got the watch back to me within 2 weeks.
Now hearing so much , I'm also very concern about the servicing issue of independent watches. That's one reason I hesitate getting a JDN, a Haldimann , a Vianney, a LF though I really think they are awesome and I simply adore their watches.
It just seems like these watches are not as simple to service as compared to a 3 hands timepiece such as Simplicity or Observatoire.
My heart says independent but my head directs me to the 'mainstream' independent which to me means Richard Mille, Grubel Forsey, FP Journe, pretty limited...sigh.
Again, my apology, don't mean to contradict what you said .
Thomas, I wish you a Happy Chinese New Year ...GongXiFaCai 
*CL