The A-188-1D is a fantastic delay module. It's slow enough that the clock signal doesn't get audible that often, in contrast to the faster A-188-1B. If you want a delay, get this D version. If you want a flanger, get the B version (or another quicker one) instead.
So how good a delay is it? It's not at all a pristine, digital one full of clarity. Quite the opposite: it's an old fashioned, analogue, imperfect, wonderfully quirky delay with bags of character. Instant Delia Derbyshire style sounds!