Most people refer to them now as "drop in coil tanks" though the names sort of change each year it seems like. Clearomizers are generally more like the CE4's. (At least that's what comes to my mind when I think of a clearo).
TVF8's can produce some pretty hefty clouds and is a sub ohm unit, but rather than build your own coil, you "drop" a coil in and go. it's a convenience thing. (Like me, I use drop in coils because while making your own coils is the way to go, I just love the convenience of drop in coils)
Another benifit to building your own coils is that it's cheaper however, please, for the love of vaping, look into battery safety. We've shied away from rebuildables not because they aren't awesome but we've had some....situations in which users were getting ahead of themselves. (Ridiculously low ohms, mixed with the wrong battery type, on a mechanical mod = a bad situation)
We have a good rebuildable community here on the forum (see the rebuildable categories). Everyone is super helpful, it's always better to pester and ask than to be sorry