I rented two lenses for the weekend, the 25mm f1.4 and 100-300mm. I wanted to see how the image quality improved with the 25mm vs my kit lens. I took some comparison shots on a tripod with both lenses set to 25mm and the same aperture. In most cases, I couldn't see a difference when comparing them in lightroom. In a few shots, I think the 25mm could resolve a tiny but more detail, but it was less profound than even a mild enhancement in post processing. To my eye, the lens doesn't really have any improvement in IQ over the 14-42 ii kit lens. The huge benefit of the 25mm was the bright aperture and great control over depth of field. Because of this, I think I will get a 20mm f1.7, since it has nearly the same max aperture at a lower price, with the benefit of a more usable field of view for my usage. Are you guys seeing a big jump in image quality with the 25 f1.4? On a side note, the 100-300mm is a really fun lens. I just wish it were available with a faster or constant aperture.