For a rundown of all the features, my suggestion is to watch the videos. Essentially, this is all about long, modulated reverbs. For me , with a little chorus, it's evocative of Cocteau Twins more than MBV. While previously I was never a big reverb user, I find I have it pretty much always on at shows now.
It's a very long and bright reverb that can be filtered (great), but the decay time is essentially static. The decay knob is really a dampening knob, and while it does reduce the high frequency decay the low end rumbles on. This approach makes sense in that the reverb they designed is the one you hear, but it makes it a little less flexible. Very short reverbs are not really an option!
I use it on the middle setting, where the X causes a ramp up effect which is great for either doing reverse-reverb esque sounds or allowing you to keep your guitar transient intact.
The octave down setting, while cool, is not something I could see using in a band setting. However the Dream's "latch" reverb is perfect for those who might want to create pads or beds. I often find myself using the sustain button to create little noise walls during jams.
Overall, great pedal. Does its thing, and its thing is very cool.