I ordered the Snow Stage II kit back when we had a group purchase. But I sold it to another member, I didn't like the arrangement, and it would be almost useless with that small stock tank.
That said, I have been looking at installing one on my truck and also on my Project Cobra'33. I have to say I like the Cooling Mist unit better then the Snow or ATS units. In particular, I like the way the Cooling Mist unit is all self contained and how the pump mounts to the coolant tank. This was one of the main reasons I sold the Snow kit, I just had no room to mount the pump and that small coolant tank. Where with the Cooling Mist kit, the mounting is not a problem, you can put the thing in the truck bed, say inside the tool box and order the large coolant tank and be done with it.
Also, the Cooling mist kit does use EGT and Boost to control the amount of coolant sprayed into the engine just as the Snow kit does on the stage III. I think the big difference is that Snow was the first, and many have purchased his kit, thats why so many are for Snow, not that they have looked into the Cooling Mist or ATS unit, just they have his kit and I guess that means it must be superior. Cooling mist has the benefit of Snow experiences, both good and bad, and since there kit is newer, they have solved some of the mounting and installation problems that Snow never did. The two kits both use the same pumps, if you look at each site you will see that. The rest of the stuff is simply plastic hoses and a orifice. I'm not sure if I'm ever going to buy one for the truck (if I did, then I would go ahead and get the ATS intake manifold, so see who that adds up), but if I did I would go with Cooling Mist right now.