This module looks deceptively simple, but make no mistake: This is an advanced module. True to Doepfer style, it does only one thing, but that it does really well. Veteran Eurorack users will appreciate the fact that this module saves them around 1500 Euro if installed in the rack.
So how does it sound? - If you are after the sound of John Cage's 4'33", this is the module to get. It will also make your rack sound better overall, because you have more time to RTFM for your other modules. My favorite patch is to attach a contact mic from the Koma Field Kit to the module and run it through the Strymon Starlab - gently tap on the module and you are in Brian Eno territory. If you feel adventurous, loosen the screws a little for a more gritty sound.
Are there any other modules that do the same thing? Not really. I heard rumors that Behringer is working on a cheaper version, but it likely won't come out until at least two years from now. There may be a Roland Aira Boutique version but it's probably 1U/2HP only.
There is also another version by Doepfer in vintage black but I haven't tried that one. A friend of mine knows someone who has an uncle who has a neighbour who says that the black one doesn't sound as good. Make of that what you will.