I made the OP-Electronics Spring Reverb and the Ruthenium Spring Reverb projects. IMO, the Ruthenium is more practically usable than the OP-Electronics unit. The OP unit is a lot noisier (which is also cool if that's what you like). I just found it a lot harder to dial in a sweet spot on the OP for just a good amp reverb type of sound.
MAO did a layout for the Ruthenium here if you want to take a look: