Art, I have no experience with the Olympus 4/3 system, but I have a 28mm Elmarit ASPH and it's a peach of a lens.
My lens is the first aspherical version (#11 606) and I use it on a Leica M240. It's small, light, sharp and great for travel.
The second ASPH version (#11 677) is supposed to be a bit sharper (especially in the corners) but I've also read that, on a 24 MP camera, the difference isn't that significant. The bokeh on version II is claimed to be superior.
Here's the link to Leica's page on the latest version of the lens. As you can see, the MTF charts and the distortion numbers are impressive.
https://us.leica-camera.com/Photography/Leica-M/M-Lenses/Elmarit-M-28mm-f-2.8-ASPH2LensRentals has version II available in case you want to take it out for a spin on your OLY.
Best,
Jeff