I like the lucas also, you can find them in any big truck stop. I notice the gal jugs of the injection cleaner are harder to find, but definitely cheaper.
I tried the cummins injection cleaner after not using any additive for a while after reading an article in tdr about it. I noticed the difference. It definitely worked.
I've been using Amsoil and others for an antigetl. Amsoil, (and power service) are more expensive than others for the antigel part of it, and I don't think they are any better than a cheaper antigel (like howes) I usually use Howes unless I get to the Peterbilt dealer, and they have some stuff (works just as good) for $3. 05 for 700 gal, but I forget the brand. I've used it in the dodge, but usually use it in the big truck. . .