It just so happens that I do. I would say that at this point, with my current equipment (no other tubes in the system), it is something I can't live without. It adds solidity, dimension, even more oddly, clarity, particularly to the mid-range. Without this gizmo, the music sounds more, hmm, 'grey', flat.

The three different tube types do actually make quite a difference - I'm fond of the push-pull, it softens the treble a bit more than classic tube.

The downside is needing more cables, and they should all be of at least the minimum quality you would desire from a single cable.

I actually don't find any noticeable differences using in pre-amp mode, into the preamp inputs - that way, you can still use balance controls, remote volume control etc. I just twist the volume control to full on the iTube.

The 3-D sound and bass boost options can also be very effective, but obviously depends on the rest of your kit and room setup.

Certainly worth a try.