Just depends if you fancy the durability of titanium, or the clarity of a crystalline vapor path.
I havent used a banger and coil extensively. Banger and torch, yes, but I havent done any kind of side by side with the DCup and quartz banger/coil combo.
However, I kinda think
@invertedisdead has kinda given the answer, really. I'm failing to see any criteria that might change this. I suppose the only thing temp consistency. I can only assume that the coil being encased in Ti keeps temps way more stable than a standard banger and coil thats open to room temp.
Of course, assumptions are pulled out of ones ass, so...
Personally, I break bangers, and I've had a few falls where a quartz banger would definitely have shattered. If I'd had a sapphire dish in there, that would have gone flying across the room.
Ok, so there we go, theres another plus for the DCup. The lid means that your expensive sapphire insert wont be falling out should the DCup fall over.
TLDR; 1. Temp efficiency. 2. The lid keeps your insert safe. 3. It wont break