Thanks, Cole, those are interesting observations. Shelf life is absolutely a consideration, and one of the reasons I appreciated Zolotoe Serdtse which is also very firm. But you can also have a thin skinned and less firm tomato that has great staying power
.. however these firm Russians do have their place and they certainly are sweet and enjoyable. I haven't tried any of the ones you named, but we do have a common interest in finding that perfect early yellow determinate. And orange... I love the orange ones... gotta have every color.
Definitely looking forward to the JF!