I'm using a stock 1.5 DC Titan and I never thought I'd be saying this but it almost puts out too much vapor. It doesn't leak, it doesn't gurgle, it hardly ever gets any liquid in my mouth, I don't need a syringe to fill it, it's totally silent except for a bit of a whistle if I hit it too hard, the stems are super easy to replace, and the drip tip doesn't even get uncomfortably hot like all of the other top coil units I've tried. I really don't see how it could be improved. My only complaint, and its a small one, is that most of the stems I've tried required a small adjustment to the ceramic cup to not pinch the wicks.