The AT8022 is a direct competitor to the NT4, as it costs the same amount at approximately $550. It's cylindrical, rather than the Y-shaped configuration of the NT4, as both of the stereo diaphragms are contained within a single capsule. This parallel design means that the AT8022's diaphragms can have a much larger surface area. This allows each diaphragm to be more sensitive, and produce a greater degree of clarity.
The Neumann KU 100 is designed to simulate the performance as a pair of human ear. The KU 100 is a life-size replica of a human head, with a pair of condenser diaphragms in place of the ears. It's designed to capture the sensation of physically being in a space, with the sounds picked up by devices that closely resembles our own internal "microphones." According to technical information on the Neumann site, the KU 100 is aimed particularly at recording sound-scapes from locations, rather than music, and gives the best results when listened to with headphones.
The CUW expands on the separate capsule concept used by the original NT4. It has a single body, with two diaphragms on metal stalks. However, unlike the NT4, the capsules on the CUW can be pivoted and rotated. The idea of this is to allow you to create a stereo image of any width you wish. In a confined space, they can be positioned almost parallel to capture the slight variations in sound within two halves of a recording space. If you head outside, the diaphragms can be positioned at 180 degrees, back-to-back, offering the widest stereo picture possible.
Instead of a pair of diaphragms, the SoundField microphones have four, arranged in a static cube. They're to be able to pick up sound from any direction, but also to commit a sense of that direction to the recording. An internal processor decodes the four channels of directional sound internally, before the signal is sent to the recorder. The proximity of the diaphragms means that recordings won't suffer from the phase-canceling effect that can cause a lot of binaural recordings to sound thin and reedy.