The newly announced Logitech G910 Orion Spark RGB mechanical keyboard is based on their own mechanical switch, developed in partnership with Omron, dubbed "Romer-G". It supports 16.8 million colors in the backlight under each individual key. Logitech will provide software to control this lighting and an SDK for developers to integrate custom functionality into their game. It includes nine macro buttons with three profiles.
The Romer-G switch is (at least currently) exclusive to this keyboard. It is designed with a very small actuation point, 1.5mm from the top of the key. This means that you finger will need to travel less distance, and thus take less time, before the action is registered. From a feeling standpoint, they have a soft spring and a tactile bump at the point of actuation, but no click. Logitech did not comment on whether the G910 contains o-rings to further dampen the sound.
The switches are designed for high durability as well, with an expected lifespan of 70 million keystrokes (compared to 50 million advertised by Cherry and 60 million for Razer). That said, mechanical switches are designed to be put in industrial and medical devices and left unmaintained for decades, so I am not sure how practical that advantage will be.
Their partner, Omron, also collaborates with Logitech on mechanical switches for mice.
The Logitech G910 Orion Spark RGB in planned to be released this November for $179.99.