The neogeocd controller may not be the best choice for fighting games, i prefer the neogeo stick more, but it does not have a newer release which supports the xinput.
Also, bear in mind that the 2018 release of the ngcd style controller did not follow the design of the click-style joystick of the original controller, plus the button layout is switched. So, even of its low price, neogeo fans should not buy that.
However, for the 8bitdo one, it officially states that “Featuring the iconic classic click-style joystick”. So, it will be sth totally different from the 2018 one, i am very confident to this one according to my experience on its other classical controllers, it always try to follow the design of the original.