Really haven't seen enough of Danny Ings but the concern would be that he's a Ricky Lambert type, stands out in an average side but simply doesn't have the class to step up and make a big contribution at a higher level. On the plus side, he would provide work rate, a threat in the air (which we badly lack) and a decent finisher, plus he is a different option from the other strikers.
Berahino seems to me to have a higher ceiling, young, confident, very quick and the physique to go with his natural ability. He would be perfect to step into Sturridge's shoes when the inevitable injuries arise and perhaps put pressure on him to perform more consistently.
Said it before but I would love to see us buy both Ings & Berahino at the expense of Borino and Balotelli, we would have a hell of a strike force then with Origi arriving.