s The OM bodies are nowhere near as rugged and well made as a Nikon F or F2. The OM-2 and OM-4 are useless without the battery. The Oly lenses are excellent, by and large, but the Nikkors are if anything a bit better, sometimes a lot better.
The Air Force field tested Olympus in the mids 70's and both the LA times and AP tired Olympus, but all found that the OM 1 was not as rugged as the Nikon F or F2. I am not sure how a OM 4 would have help up.