I think it's one of the best fifties I've ever shot. Sharp wide open even.
Mine too - comparable to the v3/v4 M Summicrons that I used. And my OM 50/1.4 (> 1.1Mio) is very good as well, comparable to my v2 M-Summilux.
My conclusion of these discussions are:
1) most Zuikos had strong sample variation. And I've experienced it with other focal lengths as well (28/2 and 85/2). If you have a good Zuiko, keep it.
2) newer lenses are likely better, and if only because the manufacturing process must have improved.
3) Macros
have to be built to tighter tolerances. The impact of sample variation must be less when you look at non-macro behavior.
Also, on a tripod, with normal cable release use, I get "sharper" pictures with my Nikons (F, F3, and FM) than with my OMs (and I've tried OM[1234]). Then again, Nikons are louder. Must have something to do with how mirror damping is implemented and sequenced with the shutter.
Cameras are not just light-tight boxes. I like my current OM1 and OM2 bodies. But since I've tried the Nikons, I will continue to use OMs hand-held only.
One more note for you tripod users: if you want best results with your OM1, fold up the mirror before exposing. And at exposures longer than 10 sec, the viewfinder can leak onto film - found that out only last year. The best remedy is an eye piece cover as made for Pentax cameras (it fits).
Roland.