As far as I'm aware, the Nirvana, Ultimate Nirvana, and Absolute Nirvana are the ones using composite technology thus far.
When Brunswick contemplates new releases they target a desired ball motion, or spot in the line-up that needs "refreshing", so in time there will likely be additional balls released using composite technology.
Their other coverstock formulations are VERY effective, too, so although this thread addresses specifically the ECS technology, it should be understood that the others are not less effective when used in their targeted conditions.
It's almost like asking a parent which of their children is "best", when all probably excel in their own ways, and are not loved any less than the one who becomes a heart surgeon...
I'm not privy to all the information that the product specialists have at their fingertips, so perhaps one of them can clarify if I've said anything off base...