Surprise!
At one coat, there was a huge difference in opacity:

(middle and pinkie are Nubar Brilliant, all the other fingers are China Glaze BFF)
What about two coats?

Four?
It took SIX coats of the Nubar to match the opacity of the China Glaze:
Not only do I like the linear better, it's cheaper and has better coverage! I'm glad I didn't pay $9.50 for Nubar Absolute but instead grabbed a bottle of China Glaze 2nite from 8ty8beauty.com for $2.99!