I stumbled on this by accident. I had every intention of using my Grand exclusively with every atty I own and maybe never ever using a carto again. And then I was cleaning bins and found a bunch of forgotten IKV 901LR Cartos....I primed one up, filling it only enough so that it wouldn't self destruct. At first, flavor was kinda muted but had promise. I stayed with it and within an hour, it was maybe the most flavorful, fulfilling 3.7V vape I had every used. I've used this carto on my Darwin and other mods and it was good. But uneventful. So uneventful in fact, I forgot I had 10 of them sitting around! But anyway. It almost tastes more like an atty. Very clean and nice. BUT you only have to squonk at your leisure. Maybe every 10-15 hits or so, if that and only because you feel you probably should. I have never refillled the carto after the initial startup and it just provides a continuously consistent flavor extravaganza! I am usually a little lukewarm with IKV. I've had ups and downs with his stuff to be honest. But if you can get past the carto thing, you might want buy a few of these.