Almost all of the instructors I've ever flown with have been civilian, and have varied from absolutely superb, to pretty awful - but with a big bias in favour of absolutely superb.
(I have flown once with an ex-military instructor who was both a superb pilot and a superb instructor, and also with an ex-military person whose flying is mostly civilian, so I count him as a civilian instructor. So not really enough experience of military guys to have an informed opinion.)
FFF
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