What's the difference between Sonido and Flash step?

Is there a significant difference between these 2? Except the sound of course. I remember Ulq saying to ichi while in Vasto lorde "he just used sonido?! BAAKAANA", I mean it was white who is a hollow that used sonido, so does this mean only hollows who are like the espadas can use sonido and humans/soul reapers can't?