The original LunaSix is my main meter, along with a Weston Master III that I like using with the Invercone.
A meter movement is very difficult to get repaired properly, it's a job for a watchmaker really. The LunaSix has been in my hands since the late 80s or early 90s, it's still accurate and reliable after being recalibrated ca. 1995 by Gossen. I have a LunaSix 3 and a LunaPro NIB for backups, along with an NIB Master III.