I think the Vivi Nova is the easiest to dryburn of all the clearos I've used. It will burn all the sugar gunk off in a couple of minutes. There are some good videos on dryburning if you haven't tried it yet.
My Vivi Novas last for months. In fact I haven't had to throw away a coil head yet. I don't use many dark or sweet juices though so I'm sure that makes some difference. I use mostly menthol 70/30 PG/VG though and it doesn't gunk them up as quick as other juices.
I use mainly cinnamon and VG and mine are hanging in really well.