The Harley Benton Classic Flanger is an amazing piece of kit, it's very robust and well made - solid metal, great action on the foot switch and firm control knobs, which is important as I do like to get my fingers around a firm knob. The holes are also very tight with good grip.
The effect is exactly as one would expect, it gives that great whooshing jet engine sound in varying degrees: one can set the speed and re-gain fast for a tremolo effect, or kick everything down to 10 o'clock except the speed (at say, 2 o'clock) to get a pseudo chorus sound.
I picked a flanger up specifically so I could get most of the way to a Chorus, Phaser and Flanger in one box - but in reality I was mistaken and that is my fault. This is definitely a great sounding pedal, but if you want a chorus or a phaser sound, at the price of the HB pedals you are better off getting dedicated pedals for them.
The art on the pedal is pretty rubbish design-wise, but the white and black colour scheme is OK and the execution of it is perfect: there are no chips or dents, or masking errors at any point.
I would give this pedal a 'good' rating, because it does what it says on the tin with very little fuss and great quality.