What's the difference between chinabjd and oueneifs?
History time:
Back in 2011 to at very least 2014, AliExpress just wasn't a thing for recasts. You had to place your recast orders by Skype, mail, MSN at best. Pay by PayPal, and wait.
At that time, there was very limited recast sellers that were shipping worldwide, and the best was known as "S/L" (as if in "Steven Chen & Luo Luigi", although pretty sure they had other names and it was a team involved).
Eventually, that society came to be known as "China BJD", and, not long after, Steven parted from Luo (for business management issues they couldn't resolve, and, are unknown for the rest of the western world, as far as I know at least).
Therefore Steven keep the "China BJD" (best recasts in the market) name, and Luo took the name of "Luo Luigi" (poor random quality for most part).
And it's speculated that the quality issues were the reason why the two split.
Later on, as "China BJD" was a pretty generic name, and other brand new sellers were using it to sell bad quality dolls (by confusing the buyers). Steven Chen an it's team made the name "Oueneifs" and filed as their own. So no one else in China could use such name.
But mostly so people wouldn't be confusing their store for other. Regardless of what antis think, reputation is a thing they take quite seriously.
So basically, if you get the real original "China BJD" store and "Oueneifs" store, are run by the same team (possibly divided in two different teams, but maintaining the quality standards and costumer service they're known for), even if they give priority to the Oueneifs store most times, it's the same group of sellers.
Hope this clarify things for you.