My Gustard x16 is replacing a Topping D70.
They both sound great, but the Gustard is better for me because the Topping D70 does not have Bluetooth.
Volume control with remote or knob works great.
My only complaint about the Gustard x16 so far is that the display of the volume is tiny.
I want to volume display to be at least 3 times bigger than it is. This is a minor problem that may annoy you if you use the Gustard as a preamp.