I mostly use EVOD or T-3's now, but I carry my 510's with cartos as a backup. And you know what? I still like the way they hit - when they hit right. They're pretty low res, so it's a hot draw, and it definitely isn't as good for a real FLAVOR, but I still like it.
Tell ya what I DON'T like - I've been getting a real difference in how juices taste in a Vivi Nova! I was sort of trialing those
three units (minivivinova, EVOD, and T3Mini) and I get a real muted flavor - PLUS something sort of metallic off the vivinovas.
Anyway - I've probably now got a 3-year supply of cartos, cause I stocked up a little before I outgrew them for regular use...