Vivi novas definitely.
I was using the DCT cartos with tanks a few months ago and I kept swallowing ejuice! I initially bought the 1-hole cartos but kept getting dry hits so I ordered the 3-hole varieties next-- it's a hit-and-miss affair. Some cartos work perfectly for around 2 weeks then the flavor got muted after a while. Some would flood immediately, and some would wick slowly. I removed the tank to keep the juice from getting sucked into my mouth but I kept wasting ejuice coz they kept leaking; after you dripped your juice and put it down, you'd notice the ejuice leaking into the PV well(?). So I bought a dripshield and that solved the problem of leaks but the muted flavors after using them for a long time bothered me. Cleaning them would improve the flavor but worsen the backflow... the only solution was to buy new ones every so often.
Finally saw the vivi nova and I've been using them ever since. No leaks so far, no more of the juice going back to my mouth, vapor production's awesome, and the flavor from my ejuice is good. Only thing that kept bugging me though is that I heard you'd occasionally get a short because of the way they're made. I tried rebuilding one and it was performing well but after I heard of the reports, I threw it away... I think it was ninja who said that even though you'd think they were performing well, you'll never know when they'll short out.
So now I've just ordered a genesis DID clone to see if it would perform better than the two. But as for your question, I would prefer the vivi nova.