My 757 UTC was purchased new in August of 2016. I purchased it from the original owner on Sept 2016 [on Helmut Sinn's 100th birthday]. It's the perfect Project Manager's tool watch with many features that all come in handy on a daily basis.
About a year after my purchase I noticed the chronograph center hand did not reset to zero, but closer to the 58 sec mark. Having owned many 7750 powered watches, this was a first for me. Took it to my trusted watchmaker who suggested it would be best to send to Sinn. I called RGM to review. I also requested the possibility of replacing the dial with a 757 or Diapal dial as well as the UTC hand w/ a white version since I'm colorblind and really can't tell what color it is [although I come to find out many who are not colorblind can't agree on the color either]. During the phone conversation RGM said they would find out.
On 4-23-18 I received an email from RGM confirming possession of my watch. Shortly thereafter another email confirmed requesting info on when and where the watched was purchased, which I forwarded. On 5-2-18 RGM replied that Sinn does not allow swapping parts with different references [a shame but not the end of the world]. The watch would be repaired with a 2 to 4 week turnaround depending on what was discovered once the watch was on the workbench.
Yesterday I received an email from Fed Ex that a package was on the way, signature required. It was coming from RGM, although I received no email from them directly. Today my 757 UTC was delivered, everything perfectly aligned [including the bezel, which was ever-so-slightly off center]. The paperwork read: Regulated, Realigned Sweet Hand, Replaced Moisture Capsule and Gas Under Warranty, Price 0.00. I had no idea if this was under warranty but that was a pleasant surprise as was the regulation and moisture capsule & gas replacement. I essentially have a brand new watch. My only expense was shipping to RGM.
Although the turnaround was 7 weeks total, I'm very happy with the service and thrilled to have it back. Others have had better or worse experiences but wanted to give mine in an effort to inform the Sinn community.