For me its safety and convience.  I'll pay more for 28%N.  Also, most of my N goes on sidedressed with a cultivator-1000+acres on a 6-row rig every year!!!  We are able to cut our N rates by 25% or more by sidedressing and cultivating.

 Also, maybe somebody can correct me if I'm wrong, but I believe that Anhydrous was used somewhere, Vietnam?, in a war to make runways.  They injected it to compact the soil so airplanes could land on it.  If that's the case, I don't need any extra compaction on my farm.  I've also always wondered what it does to soil life, microbes, etc?  If its so unsafe for us it can't be that much safer to the soil life.  Just some thoughts.

 Not many people fall apply N here as there is too much chance of it leaching till spring.  The one Co-op does lots of spring application of anhydrous for farmers.

Hope this helps.