Maybe mine is just a lemon...
I've had good experiences with TC Helicon gear in the past, so I jumped on this little unit when I wanted a simple vocal delay that would help settle my vocals into a live mix and give them a little more flash. It seemed like a great idea, because I didn't need anything else like harmonies, pitch correction, reverb, compression, etc. that you are paying for with a more expensive unit.
This thing appears to be of decently rugged construction, and it sounds fine (the "Analog" button, which applies a HF roll-off to the delay signal, is a really nice touch). But mine doesn't function consistently.
Problem #1: The delay time usually doesn't match what is selected on the first knob. For example, tapping the tempo is supposed to set the quarter-note time, but selecting quarter notes on the knob produces a delay at twice the tempo I tapped-- an eighth-note delay, in other words. I move the knob to the eighth-note setting, and nothing changes. This problem is inconsistent; twisting the knob back and forth a couple of times and then turning it counter-clockwise back to the quarter-note setting will correct the problem about 20% of the time. I usually don't bother. I just tap my tempo in half-notes instead.
Problem #2: The unit will occasionally "lock up" and I'll lose the ability to tap tempos at all-- holding the button down simply toggles the bypass on and off as though I had stepped on it normally. It stays like this until I unplug the unit for several seconds and plug it pack in. Since doing so produces a loud pop in the signal line, this is not an option onstage. I just have to turn the unit off or deal with a delay set to the wrong tempo.
Problem #3: The Feedback and Mix knobs have virtually no resistance and spin freely with almost no effort. I move around on stage a lot with my mic in hand, and simply being accidentally brushed by my cable is enough to severely tweak these knobs. More than once in rehearsal and on stage, I have suddenly found myself with either no delay at all, or (much worse) no direct signal and near-infinite delay feedback. Because the input jack is on the back of the unit and I'm in front of it, the cable is constantly at risk of being pulled across the knobs. If I flip the unit the other way so that the input jack is facing me, I can't tap tempos without stomping on the knobs. This problem would be nonexistent if the knobs were stiffer.
I really wanted to like this unit, but I feel that I didn't get my money's worth. It feels more like a toy than a serious tool at this point. I'd rather overpay for my delay by buying something with a bunch of features I don't need if it means that the thing will actually work the way it's supposed to.