First off, the Canon EF 35mm f/1.4 L USM sold for well over $999 most places before it was superseded by a new and improved model. About $1,350-1,400 was the common price of the original lens for many years. Now that the EF 35mm f/1.4 L II is available and has been confirmed to be a significantly better lens in terms of its optical performance the market value of the older model has gone down. The new still hasn't worn off the EF 35mm f/1.4 L II that has only been out a few months. Eventually you can probably expect the price of the newer lens to settle down from its introductory price of around $1,800 to somewhere in the $1,400-1,500 range, depending on how the yen/dollar exchange rates fluctuate.
The price difference between the original and II version of Canon lenses is similar to the way the price of a 2016 automobile will drop after the 2017 version of the same car has been introduced with a significant update in the design or performance of the car. The dealers will reduce the price of the older model to move the remaining inventory.
Samyang and Rokinon lenses are often designed and manufactured by the same company and marketed under a variety of names. Bower, Vivitar, Falcon, Walimex, Opteka, Bell and Howell, Polar, and Pro-Optic are other names under which the same lenses are sometimes branded. The "chipped" versions mean they will communicate aperture settings and other lens identifying information with the camera for which they are specified. All are manually focused lenses without the ability to use autofocus.
The Tamron and Sigma offerings are each their own design but do include autofocus in their capabilities. As with most third party lenses, the AF usually isn't as fast or as accurate as Canon's own lenses with the same focal length and maximum aperture. Third party lenses may not work with newer camera models introduced after the lens was released without a firmware update from the manufacturer. Recently both Sigma and Tamron have created products that allow the end user to update the firmware on their most recent lenses without requiring the lens to take a trip to the nearest factory service center.
Zeiss is a German maker of lenses that has long been regarded as some of the best in the world. They are also typically manual focus lenses. Some of their current offerings live up to the high price and the reputation the name has built over the past century, others don't.
Different lenses are like different cars. Some are made to be budget savers and offer only the bare necessities. Others offer different features. One may be fast and sporty in the way it handles, but only has room for two persons. Others may be heavier and slower but able to accommodate more passengers and/or cargo. Others may offer a blend of performance and utility. Others may be seen as luxury vehicles.