I'd been considering buying one of these for a while, then I saw Robin Rimbaud (Scanner) using one in a live stream, and after a quick back and forth with him on Twitter I knew it would work perfectly with what I'm doing.
My setup is e-bowed lap steel through multiple effects, a sampler, plus various synths including a Bastl Kastle Drum. These go into a small mixer, with the two outs going into the Soma Cosmos's L/R inputs. The Cosmos's L/R outputs give me a stereo signal at the end of the chain.
As they say in all the reviews online, the Cosmos is NOT a looper, so if you're looking to create multiple repetitive loops go for something like the Boss RC-505 Mk II. The Cosmos is more random, and in fact it's impossible to completely control the final results because the algorithms generate loops which are constantly shifting against themselves. There are multiple settings which determine the "depth" of these shifts, from simple drifting ambience to a full on cacophony of layered sound. Find the feedback sweet spot and it'll carry on forever while you go to the bar for a pint!
The build is really solid, as you'd expect for this kind of money. I imagine the metal casing is pretty much indestructible, and the dials/buttons/switches are really good quality. The algorithm selector positions click into place very positively. Oh, and the sound quality is great.
So, the Cosmos is good value even at a touch under £600 - if it's the right tool for what you want to do. If you're loaded, why not get one of these AND an RC-505!