I had extended travel ICON Coilovers in the front and ICON piggy back shocks in the rear. When I upgraded to Remote reservoirs w/ CDC Valves (front and rear) I was pretty dang impressed. I am not sure I would say I was $3000 impressed, however. Luckily for me, after selling my shocks and coilovers I was only out around $800 for the upgrade. I was surely $800 impressed.
I think that the CDC Valving is good for me because of all of the different roles I demand my 4Runner to fulfill.
Through the adjustment valves I can:
-Increase the dampening to of my rear shocks to perform better under the extra weight of my roof top tent, large Pelican cooler, 2 dogs, gear, wife, etc. etc.
-Decrease the dampening in the rear when I take all of that out (probably around 500lbs).
-If I am going to be on a long road trip that takes me through the passes I will dial the front and rear both all the way up to 10 (or H, as the knob reads) and enjoy the improved handling due to NOTICABLY reduced body roll for the high speed curves.
-When going off road while I am airing down I will typically turn all the knobs to 1 (or S, as it reads) and enjoy a much more comfortable ride.
All in all, I think they're great because throughout the year I travel such a large variety of terrain, and in so many different cargo/weight configurations. Whether my 4Runner is empty or crammed full of gear, going on washboards or running up and over a mountain pass, I can always count on a comfortable ride, and respectable handling.
If I had one weight configuration through the duration of the year and/or only went offroad a few times a year, I don't think I would really appreciate the upgrade.