Worth the splurge?
San Marzano: $7.89
Standard tomatoes: $4.69
Yes. San Marzano tomatoes broke down into smoother, fuller-bodied sauces with more balanced flavor, an advantage clearest in a simple, three-ingredient sauce and less pronounced in a complex marinara. They're worth the splurge for tomato-forward soups and simple sauces, while less expensive whole peeled tomatoes work well when stronger ingredients are present.
For my money, whole peeled tomatoes are the canned variety worth keeping at all times. Harvested at their peak and promptly canned, they can do anything diced, crushed, or pureed tomatoes can, but better. Mash them up as they simmer in a braise, crush them by hand for a chunkier sauce, or blend them smooth.