I've had my 135L for 4 years, love it. Probably never sell it. However, color rendition isn't necessarily its strongest asset. It's really just part of the whole package that makes it such a great lens. The color balance itself is a tad cooler than I like, and sometimes too green, so I compensate with some magenta bias in-camera. In my opinion, bokeh smoothness is its strongest asset. Sharpness, and both global and micro-contrast, are all a close second. I will find it hard to believe any current or future lenses in the 135mm focal length, will be a better overall lens. An f/1.4 or faster zoom of some kind, could possibly be a better overall lens, but would be pricey and hard to design and build. I find that much of the wildlife I like to shoot, needs such fast aperture for the low light...that none exist.