Where gear evaluation is concerned it often matters more WHO is saying things rather than WHAT is being said. In brief, I am a retired guy who has only developed an interest in photography in the past 10 years or so. I worked in the field of maintaining broadcast (TV and sound) transmitters and allied A/V equipment. I must confess to having a preoccupation with things technical and derive enjoyment from decent images whether they have any creative flair or not!
I bought the 35mm lens realising that while it is not an ideal focal length for a crop body it should come into its own on a full frame body, particularly one with a high MPX sensor. Presently I am awaiting the specs on the 5D4
It is the middle of winter in South Australia, and that, coupled with the fact that I have only had the lens for about 3 weeks means that I have not used it a lot. Have to say that I am impressed with the sharpness over the whole frame and the general absence of artifacts such as CA, lens flare etc. As with audio and loudspeakers, the best of them are equally characterised by the sounds they DON'T make as the sounds they do make. I think the same applies to lenses, where we almost get used to artifacts that don't belong there. Thus an early impression of the images from the new lens was how simple, even boring, everything looks.
An organisation promoting choral music uses me as their "official photographer" at workshops, concerts etc. During an all day conducting workshop the new lens produced far superior images to the EF-S 17-55mm f2.8 zoom and proved to be a very usefull focal length for getting all or most of the ensemble in the shot. I used the EF 70-200 f2.8 for close ups of the presenter.
I don't know if it is the price tag, but this lens seems to have largely passed under the radar of all but a few discriminating users. The on-line reviews have been pretty enthusiastic, and Lens Rentals have one of their "tear downs" on it, where they rate the build quality among the best they have encountered. Not being interested in shallow depth of field images, the sharpness at f1.4 is somewhat wasted on me!. Very happy with the lens.