I've had the Vaporesso Estoc Tank for several months now, using the EUC ceramic coils. I use it all day, every day. It's been with me touring all over Europe in freezing temps and 90 degree weather on the Riviera - in my pants pocket, walking for 8 - 10 hours a day. Also many flights including transatlantics in the cabin with me.
It has been used and abused. Here's the thing: NO LEAKS! Not a single drop! No problems whatsoever and I've only had one coil die. Coils have been lasting weeks, not days. I changed coils just because they were in so long. And flavor is excellent. Really excellent. Clean, dynamic with clear flavor identifiers. As good as or very close to expensive RBA's I have but never use now. So easy to fill, 99% of the time with no juice on my fingers at all. And it's 4 ml! This is by far the best tank I've ever had. Closest thing to bulletproof ever for me. It's a joy to use. I'm so confident with this tank, it stays in bed with me all night.....lol. It performs better than many tanks I've had at four times the price or more.
The only bad thing is that they can be hard to find as well as the coils - always out of stock. Now that I'm back in the US, I'm looking for more. (vaping in Europe is almost nonexistent).