Across the board improvements in imaging, but particularly in image height. Width is also improved, particularly the specificity of images beyond the width of the speakers. I didn't feel like my system imaged poorly, but it was the area I was most interested in improving. Upon further listening, textures are also more realistic, i.e., brass instruments have more bite while paradoxically being less grating. Minor details in the mix are now more readily audible. Not that they are forced on you, but they just emerge naturally out of the mix. Overall, its nothing life-changing but lots of little improvements with seemingly no drawbacks.
The shortblock is so inexpensive compared to some of the other items on a USB audio shopping list, that there's really no reason not to try it. I would most definitely pick one up before I even thought about swapping one expensive USB cable for another expensive USB cable.
As I said in my previous post, I used it in tandem with Cable Elevators under the USB cable for an outstanding low-budget step forward.