Pour-ons are abysmal. Gotta make sure that the full dosage is actually applied to the cow - doesn't run off, get sloshed and not even on the animal, rain doesn't wash it off soon after application, etc. And... studies have shown that the majority of the drug that actually gets to where it needs to be to kill worms gets there by ingestion - cows licking themselves or herdmates and ingesting the drug in the process, NOT because it's all that well absorbed through the skin. Those same studies show that for far too many of those treated animals, only 30-50% actually get enough of the drug to the target to kill the worms.
I would never recommend pour-ons... sure, they're easy to use, but if they don't do the job, why waste time and $$ applying them.?
There's also strong evidence that 'generic' preparations - especially the generic ivermectin products, are NOT as effective as the 'pioneer' product... Ivomec. I used to be all about saving a buck... and would buy the generic ivermectin products, but studies I've seen showed that they were significantly less efficacious. What good does it do if you save a buck or two per animal... but the drug you've administered doesn't kill the worms? Spend the money on the 'name-brand' dewormer.
Don't have any first-hand experience with LongRange... but I have some concerns about it.
There are some ongoing studies I'm aware of, comparing LongRange to a combo treatment of oxfendazole(Synanthic) and Cydectin given at the same time. Initial results, looking at ADG and pregnancy rate in heifers showed the two to be fairly comparable... but the Oxfendazole/moxidectin combo was a lot less expensive.