Dual Coil Carto Tank (DCT). When they work, they work really well, but when they decide to start leaking, there's no stopping it. Just my experience. I gave them another try about a year ago and was pretty impressed for a while (using a 2 hole dual coil carto). However, about a week into it, it started to leak and made quite a mess. Did I mention that I was on my way to work then this happened? Gave up on them after that.
I've used the iClear30 (came with the MVP2) and iClear30S (came with the VTR) and thought both of them pretty much sucked. Both leaked bad, and the 30s was mostly just burning taste the whole time I used it.
I never had a problem with the Vision Vivi Novas Tameiki. I used them for quite some time and didn't have much trouble with leaking at all other than a dot of juice on the battery connector from time to time.
Still, as you said Tam, vaping is all about personal preference. Just because everyone else loves something, doesn't mean you will. LOL!