Yes, the Slo-Mo effects were mesmerizing. In 2D they were pretty (despite depicting sometimes extraordinarily violent scenes, though I think this was a deliberate commentary by the filmmakers). But in 3D they had the uncommon quality of being hyperreal and hyperunreal at the same time, some weird appeal to your addled occiptal lobe - case in point where Dredd flings Ma-Ma out a window and the shards of glass twinkle like a gentle rain of thousands of diamonds. If someone watched those scenes purely in 2D they missed that experience entirely.