You're asking about a device that takes a digital signal and then converts it to analog signal that we can hear. The digital signal going to the device might be the same, but what comes out is not. The conversion to analog is where the magic happens and the quality of the DAC and other components makes a difference in how the analog output sounds.
Short answer is not all streamer/DACs will sound the same and there can be significant improvements in sound quality based on quality of components and level of craftsmanship.

