Synthtech / Motm / Paul uses Bi-tec pots. Winner ! ...and has overall a good look on what parts he uses .
not had any Cwejman or MacBeth. Can´t vouch for them
many manufacturers are useing stounningly cheap parts,
some even parts that i would consider to be crap ( some sort of jacks).
....there is one guy copying from the other......
most delicate parts since ever are the pots and the jacks, IMHO
Verbos fails in regards to quality with their paintjob....just to say
( i had an early module not shure if it changed ? probably not when everybody is stating them to have good or superb quality

)
a big number on that reliability deal is the serviceability of the modules
in the whole, Doepfer looks there quite good !........but the PCBs are prone to lift solderlugs off when desoldering.....be aware.
personally i think, "reliability" has also to do with many other aspects.
...if a module can be revisited and brought in a better form as a MK-II........the MK-I loses ...........at least on value.
...many modules suffer from not very good or even poor "design" decisions. my opinion