I like it. Still on the first coil, 2 weeks strong. For the first few tank fulls the drip tip got hotter than hell, but it has been retaining less and less heat as I use it. The flavor is great, but as themOnk said, it needs 45+ watts to hit the sweet spot. I haven't had any leaking issues so far.
I think the cCell coils might fit the Defiant, but I'm not positive. I picked up 5 extra of the "official" coils when I ordered the tank just to be safe. The first coil is still hitting like a champ so I think having 1 or 2 extra will keep you good for awhile.