I use it religiously (Power Service or Diesel Treat). My dealer "strongly encouraged" me to use it, explaining how they had a delivery of tractors from CIH that they could not unload. They were all gelled.
Thought I should add... this truck load of tractors was shipped from WI. I'm sure the WI CIH factory has quality fuel suppliers for their new tractors, but the fuel still gelled. I use additive for cheap insurance. Another note, I have seen studies showing how over dosing with the additives can cause more harm than if not adding anything. Unless I'm just adding a slight 'slug' during summer, I measure the doses per the instructions so I don't add too much.