Can't answer for you, but my Baker's Creek order came with Green Vernissage and I was just opening and searching the Tomato forum to see if I could find comments on this one :-) (and searching for green, I see a few negative comments about the black).

I also received the packet of black vernissage and I am trying to decide if I want to grow them. I grew yellow vernissage a couple years ago and did not like them. The plants were large and prolific, small fruits did have tough skin and they were tasteless and mealy. The color was more white than yellow, so the fruits were not so nice looking. I read a few reviews from this forum and it seems like black vernissage has similar problems. I would probably skip growing them.

Thanks for the feedback, I won't waste the valuable little space that I have to this tomato. Most reviews I came across said they were roasting tomatoes and I'd rather have fresh eating ones anyhow.