Space Spiral [Dark Rift] is a fun one. No tone control, but the modulation is awesome. I debated for a while between that and the Disaster Transport, and I'm glad I built the Space Spiral. Pairs great with a Ghost Echo [Spirit Box].
...Not to say I won't still build a Disaster Transport at some point, too. Because I've got one PT2399 left burning a hole in my parts bin.