I switched from Nikon to the Olympus OM system in 1979. I loved, loved, loved my OMs. Carried them on documentary/PJ assignments to 27 countries on five continents and around much of the US, plus a ton of editorial and commercial work.
By 1992, aging eyes made it more difficult to focus quickly and accurately on the grid screens with very fine microprisms that I had installed in all my bodies. In retrospect, I should have just changed screens and kept on using the OMs. But I sold everything, and after trying Nikon autofocus (it hunted for focus like a hound dog with a cold in its nose), I tried the Canon EOS system, which locked on focus like a pit bull. So I switched to Canon, and eventually switched over to Canon digital, which I still use for my commercial and architectural work.
At the time I sold my OM system, I had several bodies and 13 lenses. The workhorse body was an OM2n, but I also had an OM-1, an OMPC, and a recently acquired OM2S.
When I first began to use Olympus, I bought a 21mm f3.5, a 28f2.8, a 35-70f3.6, a 50f1.8, an 85f2, and a 135 f2.8. I later decided that the 24f2.8 could do the work of both the 21 and the 28, so they went on the shelf. I added other lenses over time, and on my last trip abroad I carried the 24, a 35f2, the 85f2, and the 180f2.8. This seemed to be about the perfect set of lenses for the kind of work I did. All were very sharp, and with the exception of the 180, were all quite small and light.
Over the 13 years that I used Olympus, I would estimate that about 70% of all exposures were made with the 85mmf2.
The only Oly equipment which gave me problems was the winders, which weren't very durable. I should have just bought motor drives up front. Also, I found the 35-70f3.6 to be not as sharp as I would have liked, although others have rated it as very sharp.
Now, after 18 years, I am back to Olympus for my personal work and book projects. I inherited an OM10 from my father, which I had originally given him back in 1981. However, its shutter is inconsistent, so I bought an OM2S Program from KEH and have been shooting some test rolls in it. I also inherited from my father a 28-80 f3.5-4.5 Sigma and an 28-85 f2.8-3.5 Kiron, both very clean. The prize, however, was a Zuiko 75-150 f4 in mint condition with the original case and instructions.
I am very much enjoying slowing down, shooting less, and thinking more about what I'm doing. Digital can be just too easy.