I agree that Sorghum as a non GMO has some advantages in the export markets.. and that China does not have a tariff quota on it.

In Kansas it depends.. Sorghum is offered higher than Corn in the eastern half.. though Corn is higher in the western half as the Feedlots prefer to chew through it.  "Right now" at some of the eastern terminals Sorghum is quite a bit higher.. but.. a) Sorghum harvest has just started.. b) Some of the early Corn premiums have dissipated. 

As far as yields go.. again it depends.  In a good growing environment with good moisture Corn will probably beat Sorghum.. the reason I like corn is because of a) more herbicide options including glyphosate.. b) I can turn the corn ground around back to Wheat.. Sorghum has an auto toxicity that makes establishing another crop behind it (before a freeze)... "challenging".. Dryland corn comes off here a lot earlier and we have time to bank some rains before sowing wheat.. With Sorghum.. your (usually) still fighting green plants.. the auto toxicity.. and virtually no sub soil short of very timely rains.. (and then it's probably too wet.. and late..)

So if your going to do Sorghum.. then your pretty much locked into a fallow period following it.. or another fall crop next year.  That being said.. the last couple years have favored Sorghum yields exceeding corn.. even this year it may beat corn (if we can get to it before it falls over..)  Thus Sorghum acres are increasing.. and hence so is fallow behind it.. which given the current environment.. isn't all bad.

Economically it's cheaper to raise.. we're probably not pushing the ground as hard.. you can graze the stalks.. and it provides a good wind break/cover in strips between wheat ground.. so it's definitely got a spot on the team.  It's a good option for producers to take a look at.. heck we'll probably favor it over Soybeans next year given the Soybean outlook on any double crop that we would do..  fwiw.