other reviews by notable reviewers:
Canon EF 50mm f/1.2L USM Lens Review - photo.net
[h=2]Conclusion[/h] There’s no doubt that the
Canon EF 50mm f/1.2 L USM, (
compare prices) (
review) is Canon’s best 50mm lens and an excellent performer by any standard. The fast aperture is ideal for work in low light, where focus is fast and positive. As a portrait lens, the fast aperture 50/1.2L is capable of subject isolation via its small depth of field and its ability to throw backgrounds out of focus. The quality of the background blur (“bokeh”

is smooth and pleasing.
Canon 50mm f/1.2
The Canon EF 50mm f/1.2 L USM Lens is going to be purchased by those who want the best image quality they can get from f/1.2 to f/2, by those needing a more-pleasing background blur quality than the other two 50s deliver, by those requiring the least amount of lens flare in their results or by those who need/want the best quality (build) lens they can get. I can't say that the Canon EF 50mm f/1.2 L USM Lens is as great of a value as the 50 f/1.4, but I do think it is worth the price to serious photographers who need what it can deliver.
FM Reviews - Canon EF 50mm f/1.2L USM
Description:
The EF 50mm f/1.2L USM is a peerless new standard lens featuring an ultra-large aperture for a narrow depth of field and soft background blur so loved by photographers everywhere. The EF 50mm f/1.2L USM is suitable for any shooting situation; its lens coating and construction are optimized to minimize the ghosting and flare that frequently occurs when lenses are used with digital cameras. This high-performance, weather-resistant lens delivers all the superb image resolution and contrast you expect in a Canon L Series Lens.