Newb here, I haven't tried the vivi yet, but I love my kanger mt3! (really just a metal wrapped T3) It is easy to use, and ( I knock on wood here also ) no problems. I just use a syringe to fill it so I don't get any in the center hole. Mine performs the same whether filled to the top of the center pin or getting empty. I always tighten is just barely tight, then shake it, set it down for a minute or two to make sure there will be no leaking. Then when I put it on my ego, I am careful to just barely tighten it. I think over tightening can cause a lot of problems. I love the simplicity of it since I am new. All I have is a plain ego and at the ohm it comes in it produces more vapor than the cartos I started with. Waiting for them to get back in stock since the Chinese New Year is over, and going to try a lower resistance since I only have a fixed voltage device. Since I am a newb I don't even know what my voltage is. Anyone care to enlighten me? All I know is I have a 900mah Ego, I beleive they are Smoktech although they have no name on them. Sorry to get off topic of OP, send me a pm on the voltage please.