I have tried this pedal front of amp, with good quality cables and nothing else in the signal chain. When you actually play, it does a spot-on 70s Laney sound a-la Black Sabbath - when I write spot-on, I really do mean it. Unfortunately, as other reviews both at Thomann and the general Internet are saying, it is way, way too noisy - rendering it borderline unusable without a noise gate. At first I thought I was handed a faulty unit, a quick search demonstrated that a lot of owners have the very same problem.
Is the pedal worth buying? This is really your call. When playing beefy power chords, you do get the Tony Iommi sound in spades. Pause for a moment and a way too loud noise pops up. Given the price of the pedal, I was really expecting more sound wise - how did the prototype ever passed sound quality control?
On the positive side, it is greatly packaged, built out of metal and able to withstand abuse and is really easy to dial in your favorite 70s heavy rock sounds - noise notwithstanding of course.
[EDIT] After digging around, I decided to use a battery, as opposed to my trusty power source. The noise level went down dramatically, the sound is quite good, a lot of noise went away, therefore, I am making this edit to be fair.