Yeah, it sounds weird to be honest. I get a significant difference compared to my laptop onboard card, though not through USB (I managed to already ruin the USB/power side of the Move so that the amp now only runs on battery, thanks to a dodgy universal power supply). But it works, and beautifully for that matter.
I don't know if you are like me, I mean the move is my first amp, but the first time I listened to it I was not impressed either. At the end of the day some sound came out of the box and that was kinda of the same than without it... The only significant difference was the power/volume. I could have turned deaf within second if I moved the volume knob more than 1/4 up.
And then after burn in and getting my ears used to the gear (and getting a decent set of regular cans not IEM), it becomes obvious. It's a bit like those 3D pictures: you don't see anything for ages and then all of a sudden you see the dinosor jumping at your face
... And you cannot not see the thing again anymore... It's there. You can't go back... You're proud, too.
You can see 3D images...
Same thing with headphones amps... I tried without it a couple of time and it's aweful... I just can't go back anymore. The difference is SO obvious now.
Only my Cowon D2 holds its ground but it become more and more likely to me that I will soon pair it forever with the move. I bought the velcro straps anyway, there's no hope for the poor bugger...
A marriage in heaven...