Your are likely referring to Captain Black 'Light' now renamed Captain Black 'Round Taste' due to the outlawing of the word 'Light.' I'll let others speak to quality, as I am of course biased. The tobacco itself is mostly a golden cavendish, with a just a hint of burley and oriental. It will make it the mellowest smoking of the CB blends. Compare it to Captain Black White, which has far more black cavendish with a touch of golden cavendish and burley (no oriental).
I am smoking a black cavendish blend right now from a local store. I havent purchased any captain black yet, but you would recommend the cb white before the round taste?
Probably, but it is completely subjective, of course. CB White has a deeper flavor that leans towards a hint of chocolate and is a bit more robust, which I prefer. CB white will have a bit more of a vanilla flavor and will be lighter on the pallet. If you are enjoying the black cavendish blend, you'll probably prefer CB White over CB Round Taste.