I've posted about my vintage 1963 Nivada Antarctic auto diver. I am enjoying it, though still getting used to its quirks. For example, I had it off my wrist for 12 hours and it stopped. Should be able to last longer than that? The next day it only lasted 10 hours before stopping.
Also, after picking it up and resetting the time and placing it on my wrist it didn't start back up. After resetting it again, it started up, but then stopped again. It's ticking now, but I'm concerned something is wrong. The seller told me it was recently serviced.