Hello there,
I would encourage you, if you're interested in vintage precision watches, to read "Wristwatches chronometers" by F. Von Osterhausen (sadly it does not seem to exist a similar book for pocket watches). It will answer a lot of your questions. The author made some tests with different vintage movements, but I'm not sure if we can draw any decisive conclusion wether any particular watch would be better than all others. That said, some are more reputed than others : the Omega 30mm, Zenith 135, Girrard Perregaux HF, Seiko 4520, Peseux 260, Longines 15.68Z (all of these had special versions made for observatory competition).

 

(And I know that the boring way to answer will be that it all depends on the service history etc etc...)

Well to be fair, vintage movements with a reputation for accuracy generally gained that reputation when new, not when vintage.

A few more for the list:

Vostok Precision 2809A
Zuan Shi SM1A-K
Citizen 0802

 

The problem with wristwatches is the wrist! Small yacht navigators in the pre-quartz, pre-GPS era used to use an American railroad pocket watch, if they could get one, or failing that any decent wristwatch, but what we did was to put them in a box full of cotton wool, chocked securely at the chart table, and wind them at the same time every day. The cotton wool cut out vibration and small shocks from wave impacts and helped to keep the temperature even. I strongly suspect that the observatory trials of wristwatches may have been held under somewhat similar conditions.

 

Are you asking about the most accurate movement when it was new, or the most "reliable" after 40+ years of use?

I'm no expert on the subject, but like you said, I think you're better off on a well-maintained average movement than a poorly-maintained quality movement. For example, I have an Atlantic from the 1950s with an AS Cal. 1604, freshly serviced, that is within 2 seconds / 24 hours, and I've seen plenty of more expensive movements with much worse accuracy.

 

Vintage movements with a reputation for accuracy

Thanks for your feedback and the follow-up questions. My interest, however quirky or irrelevant, is to get suggestions for vintage watches that - if I am lucky - can be made to run very accurately.

There are not many reasons to spend money, time and energy on obtaining specific mechanical watches and try to regulate them optimally from the perspective of wanting access to very accurate time. Then why not get a quartz or look at the mobile phone? Let's just say that I'm interested in mechanical watches out of a fascination with the art of watchmaking. And since I have personal interest for regulating watches I am just looking for a new object to fiddle with. But it also feels good to go on an extended trip and be able to catch trains with small margins without having to reset the watch every few days. ?

 

Re: Vintage movements with a reputation for accuracy

Thanks for your feedback and the follow-up questions. My interest, however quirky or irrelevant, is to get suggestions for vintage watches that - if I am lucky - can be made to run very accurately.

As long as you are considering a high-quality movement in general (and there are dozens, if not hundreds of these) this is probably going to depend as much (if not more) on the condition of the specific movement than on the caliber. I was hoping this was NOT the reason for your question. I think that from a collectible perspective, it could be very fun to focus on chronometer-grade movements as a theme, but not from the perspective that you are going to get them to run accurately in multiple conditions with isochronism, etc., because that will really be a crap-shoot.

 

Re: Vintage movements with a reputation for accuracy

About 10-15 years ago, vintage Longines watches were plentiful and going for laughable prices because the cases, dials, hands or crown were in poor shape. But many of them had exceptional chronometer-quality movements, if you knew what to look for. Try looking for a 12.68z, 14.68z or 15.68z movement. They are really good timekeepers.

 

Let's make the list of the very best:
-omega cal 19DDR, cal 344, 354 (including non chronometer versions 341,342, 343,351, 352, 353), 501, 504,505, 561, 564 (including also non chronometer versions 500,560,562,563,565), cal 711 ((including non chronometer versions 710,712,715,716,717)cal 751 (including non chronometer versions 750,752), 1001 ( including non chronometer versions1000, 1002), omega 321, 1041, 910,911
-longines 30l, 13.15,23zs, 25.17,280, 290, 340-355,430-433, 6641-6652,6902-6972,420-428, 846-847, 989-994.2, 995-998, 30CH, 13zn and 330
-certina 230,23-14,23-20, 23-30,23-35,23-36,25-45, 25-451,25-65, 25-651, 25-652, 25-66,25-661,25-671,25-672, 25-68, 25-681, 25-682,320-324T, 410-414
-cyma 162,163,166,167, 334-335,364,364k,365,365k,412-419,455-459,480,481,482,485
-anything made by eterna before the end of the 70's
-IWC cal 83,853,8531,854,854b,8541,8541b, 87,88,89,884/2,887
-JLC cal 410-412,436-437, 449-494,881-883,889-889-2
-rolex cal 630-635,1530-1535, 1556, 1560,1565, 1570, 1575, 1580, 3000, 3030, 3035, 3075,3085, 3130, 3131,3135, 3155, 3175, 3186, 4030 and 4130
-zenith cal 135, 133.8, 71,106,120, 126, 12-4-P,156D, 156H,2522-2532-2542-2552-2562-2572, 2522pc-2532pc-2542pc-2552pc-2562pc-2572pc, 3019phc, 3019phf, 5011k

 

But many of them had exceptional chronometer-quality movements, if you knew what to look for. Try looking for a 12.68z, 14.68z or 15.68z movement. They are really good timekeepers.

To second that, some of them were actual certified chronometers ! Longines chronometers from before the 1960s are extremely rare but they were of top quality, better than the already very good regular production (you can see breguet hairsprings, côtes de Genève, highly polished surfaces, even beveled anchor escapements on some; 27.0 in particular are very close to Geneva seal quality). I've seen chronometer versions of the 12.68z and some of its derivates (27.0 and 27.0s), the 30L, the 14-15.68z (same caliber it seems) and the 22as if you prefer automatics (I own this one ). Some 12.68z and 10.68z have even been submitted for a "Kew A" certificate at English observatory before chronometer competition was open to wrist movements in Switzerland.
If you can't find Longines chronometers, look for Longines with the 27.0 caliber (a 12.68z specially made for gold cases), they had almost the same finish as their best chronometers and can be found more easily.

I was simply looking for suggestions for some well-known examples of well-designed watches that would be a step up from these Certinas, Raketas, even more obscure eastern bloc brands etc.

The Vostok Precision 2809 suggested by Chascomm is already a very nice step up and maybe one of the cheapest chronometer tested movement you can find. Actually, for how cheap they sell, they are superior to most (if not all) similarly priced Swiss movements. It's really amazing how the soviets managed to mass produce such a high quality wristwatch. The only downside is their crappy cases and dials, most of them having aged very badly.