I picked this lens up back in January, and it has been one of my favorite wide-angle primes. 35mm is a versatile focal length as it sits right in the range between a wide angle and a "normal" lens, such as a 50mm focal length. It's great for street photography, weddings, and events due to it's versatility and light gathering capabilities thanks to the f/1.4 aperture.
Build quality is very nice. Metal mount and filter threads, with a plastic mid barrel shell to reduce weight. It has a nice solid feel, relatively small, and a nice wide focus ring for manual focusing and video work. This lens balances well on most cameras, and feels really quite nice on a full frame camera with a battery grip. On smaller cameras, like the entry level rebel cameras, the lens does seem a little large. Unfortunately the lens is not weather sealed since it is an older design, but it seems like it could take a couple drops of rain and be fine. Auto focus is powered by an ultrasonic motor. It is fast, quiet, and accurate. No complaints there.
Optically it's an older design, but it is still an excellent performer. There seems to be a little bit of variation from copy to copy, but not a huge amount of variation. I've found my copy to be incredibly sharp wide open, with stunning bokeh. Flare resistance is pretty good, and generally just adds a warmth and glow to the image. There is some noticeable longitudinal chromatic aberration wide open, and at larger apertures, but seems to be gone by f/2.8-f/4. The good news is that it is easy to remove in post. Distortion seems to be relatively low for a 35mm, and is easy enough to correct in post.
The 35L works surprisingly well for portraits, both half body, and full body environmental portraits. The fun thing about the 35mm focal length is that it forces you to really get in there with the subject and you end up getting some really great expressions and see people's personalities. It allows the viewer to engage with the photo and feel like they were there and part of the event.
In conclusion, the 35L is a fantastic lens. It pairs very well with the 85mm f/1.2L for wedding and event work. It's extremely good optically, and has a nice character to the pictures it produces. Almost everything about this lens is really quite excellent, and it is a joy to use. A couple alternatives are the Canon 35mm f/2 IS, and the Sigma 35mm f/1.4 Art, which are both excellent lenses, but I still prefer the Canon 35L.
To view other photos from this lens and view photos in high resolution, head over to my Flickr page where I have the photos posted in full resolution, and check out the results for your self!