I'm going with B.
Large brand names get that way because they spend all their money on marketing instead of actually making good products.
Diamonds are diamonds are diamonds. Provided they're both flawless (although the flaws can make them look more interesting), weigh the same, have a hardness of 10, and are decently cut, and put in a nice setting, they're the same damn thing.
Hell, I might even go for B because smaller companies often go for nicer designs instead of what the designers tell them look nice.
It's like when I go to a bar: For $10, I could Johnny Walker Black, or I could get Talisker. Most people get JWB and think they're getting a better product because they've never heard of Talisker.