I got the carto tank as well. I love it. The performance is great though the refilling method, if you aren't careful, can lead to juice leaking out the air holes. I've heard a lot of people complaining about this whole line up (the z2) but all of their complaints seem to be about cosmetic stuff, and not the actual performance.
Be gentle with the tank if you decide to get one, I had mine crack the first time I tried to put it back on.
Be gentle with the tank if you decide to get one, I had mine crack the first time I tried to put it back on.