@panini , great point!!!! If you're gonna start adding sugar, you might as well throw it down the drain and just buy some of the crappy jar sauces off the shelf.
Strictly talking about flavor.........
As far as why some feel the need to add sugar, the trouble starts with the choice of some canned tomatoes. They buy the cheap ones and those are loaded with unripe acidic tomatoes and water. I'm not suggesting buying the most expensive tomatoes available, I would just look for mid level brands and maybe a can or two of the really good ones to supplement.
Hunt's Angela Mia is a fair alternative. Red pack is a good choice too. I prefer 6 in 1 or 74-40 but can't find them in the area very easily. Point is, I tend to use a mix of ground with crushed and/or diced. As far as tomato sauce? Rarely, if ever. The other thing is, and this is just personal preference from both the Professional and home sides, don't add your fresh basil, if that's what you use, until the sauce is complete. Turn the heat off, chop it, add it and stir it. Copious amounts too. The flavor is much better and doesn't start to taste like 3 day old cut grass clumps smell.
For fresh tomatoes at the store, I look for the those that everyone have already picked over, the really ripe bright red somewhat soft type. Asking the dept workers if they have any overripe ones should not be out of the question. Just be aware for black spots, mold and fruit flies. You can eliminate those and you'll find these are bursting with flavor.
Firm and off red in color, sure buy them. But not for sauce. Throw those in the window to ripen more and use them on a sandwich. Also, if you wish to use fresh tomatoes and want a thick sauce really quick without cooking for lengthy periods, cut the tomatoes the night before, place them in a Colander lined with damp cheese cloth over a larger bowl, place that in the refrigerator and close the door. This will drain a ton of water out and then start to cook with those. There is flavor in the tomato water but you can add water back or reduce it then add it. I'm lucky enough to have a high quality chinois but if you don't,the colander with the cheese cloth works just as good. Heck, you really don't need to use the cheese cloth unless you are worried about seeds.
Hey, no matter what, this is all advice and it's definitely subjective. The discussion is as old as time and so is the variety of advice when it comes to sauce so..............
@chefbuba I wish I could say that! You lucky dog! If we can ever get the issues with rodents and wildlife controlled, I may be able to plant some San Marzano. Trouble is you need to leave them on the vine to ripen and the minute any tomatoes start to turn red, they become a target for just about everything with-in 4 blocks that fly's or crawls on four legs above or under the ground!