bydus, I haven't (obviously) tried this particular one, but I have three different rebuildables now (the Chalice, the ERA, and the A7) and none of them leak. The A7 could possibly leak if you lay it down, because it has a well that holds liquid in it (the other two don't.)....but it doesn't leak for me because I try not to over-squonk it. The Chalice....the juice goes right back down the hole and into the bottle; the ERA....the juice doesn't go back down, but unless you just TRIED to flood it, it doesn't leak, either; the A7...like I said, it could leak, but never has for me.
These new rebuildable attys are the cat's meow if you ask me. Best thing I've tried in a l-o-n-g time. (I've been vaping for almost 2 and 1/2 years and these things are game changers for me.)
I can't seem to find a down side to these things. They give me the best vape I've EVER had. I am getting really good (and fast!) at wrapping coils, so that's no problem at all. I'm sure I'll be saving LOTS of money by being able to rebuild my attys instead of constantly buying new ones. To me it's all win-win.
EDIT: About the Mini 18490....I don't think any of them will fit the metal mini or the metal 18490. The A7 and the Chalice will fit my WOODVIL 18490. I don't think the one that Rob will be selling will fit anything but the Grand or the VV Grand. All of the rebuildables will fit the Grand and the VV Grand.