Going to be a tricky one this season I reckon.
It's human nature to vote for players that score a significant number of goals, so Ings ought to be a shoe-in, however Armstrong and JWP have been revelations during the middle third of the season and continue to be so. They have been as pivotal to our turnaround in form as Ings has IMO.
All that said, if Ings gets to 20 goals all bets will be off anyway, if they aren't already.