I have tried a few of them and I am now using the Vivi Nova 3.5ml tanks. I've been using them for around 4 months and I love them. Great vapor, great flavor, easy to clean, quick atomizer replacement or rebuild, and Quick to fill. Usually only have to fill once a day. I've had no leaking problems with either of my vivi tanks. They also come with 3 different ohms- 1.8, 2.4, and 2.8. I got my newest one for $12.95 for the whole set. No complaints here. Good luck.