SD, I've tried them. Not my favourites, I have to say. I find the taste a little harsh. The "black" varieties, all mainly from the Crimea region originally, tend to polarise people. They have their fans and their haters. There's usually no half way.
Hi Italophine, always interested in your posts on tomatoes, expecially from someone that lives in "tomato land"! I'll wait and see what the Russians are like, if I don't like them, I'll go back to my tried and trusted Spanish ones, can't remember the names just now, but they taste great even when still a little green, to remind me of long past holidays in France and Spain (salad niçoise et al)!