The collage above shows three different Andine Cornue tomato plants on the same day at the same time (the day after the big frost), all grown from the same seed packet, planted side by side by side, same soil, same ammendments, same same same. If I had only grown the plant in the center I would have thought what a dud, never again because it started to decline early on and never did produce a decent tomato. The plant on the right grew pretty much as expected, with tomatoes that conformed to the description and to my experience with this variety in previous years. The plant on the left is extra vigorous, but the tomatoes are pink instead of red.
So, if I had grown only one of the seedlings that I started I had a good chance of not getting what I expected. That is, in fact, exactly what happened with one of my all time favorite varieties this year, the Aunt Ruby's German Green turned out to be a pink beefsteak.
I don't have the room to grow multiple plants of each variety that I want to grow, so perhaps I will have to give plants that don't perform as expected another try in a following year.
Another factor in how well a plant has performed for me is seed source. Paul Robeson in another one of my all time favorite tomatoes. I always thought that it was disease prone because my plants always succumbed to something when all my other tomatoes were still working hard. I always tolerated that because the tomatoes were so delicious. When I purchased new seeds from a different source my disease problems disappeared. The Paul Robesons that I've grown with the new seeds are some of the best performers and are just a delicious as ever.