I also have the Serpent SMM. Pretty good for flavour but I really can't stand the airflow noise. I have the Ammit 25 as well, flavour about the same but the airflow is much better IMO, as is the build quality. I prefer vaping on the Ammit.
If I were choosing now, I'd probably go with an Augvape Intake, I like the bottom airflow idea (albeit it comes in from the top). Very tempted to try it but a bit reluctant to buy yet another tank that ends up on the reserve bench (I mostly use single coil RDAs these days), my other tanks have been passed on. The OBS Engine Nano also seems highly regarded, not so easy to come by now and out of the Nano or the Intake I'd probably opt to try the Intake.