Cheerson Hobby is a very popular multi-rotor brand across RC enthusiasts. They are mainly specialized in small drones, but also have few successful bigger quadcopters.
The CX-20 was probably the first affordable alternative to the DJI Phantom series.
Certainly the CX-10 series has the biggest popularity. Over the years this this evolved from a basic RC toy to a very versatile drone with WiFi FPV and altitude hold.
Below you can read about all the existing Cheerson quadcopters.