I’ve used both Olympus and Nikon, and I find them both to be acceptable. We’re currently an Olympus outfit and I have both a BX46 and a BX43 for the two sites I cover. One has fluorite objectives and the other has plain achromatic objectives, but I’d like to upgrade to apochromatic eventually.
The only differences between the two is that Nikon still makes a dry 60x objective in the apochromatic grade (Olympus no longer makes them) and Olympus still makes a 1.25x in the apochromatic grade (Nikon makes a 1x but it’s achromatic).