I've just been given the above lens as it is an Olympus OM fit. I'm not usually a fan of zoom lenses and I I assumed it was just a usual run-of-the-mill cheap zoom but it really seems to be a great lens. I haven't had the time to do my standard test with a sheet of newspaper but initial shots look OK. At f8 or f11 it gives good sharpness across the frame if a bit low on contrast.
I've never heard of Marexar. The lens is well built and has 1/2 click stops on the aperture ring.
Anybody heard of Marexar or know anything about this lens?