Not that it really matters, as Brisbane potentially have both for the next 10-15 years, and I know it's a very early call, but IMO, Eric Hipwood > Josh Schache. Hipwood is more athletic (one of the most athletic players in the 2015 draft, in fact) and just seems a bit more suited to the way the game is played today.
That being said, they're both going to be quality players, and are both about five years away from even entering their prime as footballers, so who knows what they could be, or where the game itself is at in that time. I hope Brisbane give them every opportunity to play together when fit going forward, regardless of form.