I know I'm late to the party, but here goes...
Many, MANY, moons ago I bought an amazing punnet of "Sungold" tomatoes from the supermarket. They were SO sweet and delicious, that I saved some seeds to see if I could grow my own.
And wouldn't you know... I could (and did)!
I germinated two or three seeds (retaining the rest as "insurance") and they grew really well. They were indeterminate, and continued growing ALL the way through our Adelaide winter (in a greenhouse). Granted, there were SOME issues with mildew if I forgot to airate the plants enough, but they were vigorous and healthy.
And EXACTLY the same as the punnet of fruit is purchased from the supermarket! Same colour, same size, same sweetness.
Not knowing enough about hybrids (or not knowing any better) I saved some seeds from these plants and next year, planted them out.
Again, perfect germination, same fruit as parent. No problems.
This continued for four successive generations until I just stopped growing them.
I should see if I can find those seeds (from a few years ago, now) and see what happens!
I never knew to expect different children, and I never GOT different children!
Perhaps if I could find them, it might be worthwhile growing them for sale/sharing/experimentation's sake?
Not knowing enough about hybrids etc