Deb: You most likely will not find the blacks I like at a local nursery except for CP and maybe Black Cherry. If there is a local heirloom/OP tomato grower in your area they may have some or will grow them for you for next year.
Each of my favorites have a unique flavor. Some like to say they have a smokey flavor but what I taste is a combination of sweet and traditional tomatoey flavors with undertones of spice. Sort of like what wine tasters say they can detect.
I like great big chunks of tomato or slabs that fit on a sandwich. Cherries don't do that. Black Cherry tastes good enough for a snack.