According to this, Blackprinz has more roasted flavor than Midnight Wheat:
Subtle, smooth, no bitter, astringent, dry flavors or aftertaste, very delicate clean flavor,mild roasted malty flavor Bitterless black malt that can be used in any recipe calling for debittered black malt. Blackprinz® Malt delivers colors plus more roasted flavor than Midnight Wheat Malt. Good for Black IPAs SRM/Lovibond = 500L Origin: USA