Depending on how you cooked it, the difference might be subtle enough that only someone familiar with it would notice.

Try eating the tomato raw, like an apple. A good tomato is wonderful with just a sprinkle of salt.

I only started noticing the difference after I grew my own heirloom tomatoes. I was amazed when I ate my first harvest, fresh off the plant. I had never tasted a tomato before in my life! Basic supermarket tomatoes just taste like water.

Not experienced, but (1) unless tomatoes feature prominently in a recipe, the details of their flavour won't have that much impact, (2) for any expensive protected-origin kind of stuff, there's a chance somebody just took the plain stuff and relabelled it.