many canned tomatoes are great for stew and soup, but for red sauce you will be amazed at what San Marzano or Muir Glenn will do . sweet low acid
amazing...give it a try I get them at Cosco in the #10 restaurant can and portion them out or make a big batch of sauce and freeze a bunch.
I'm with Andy on the MG being acidic. Also, I had a bad allergic reaction to them once.
I use San Marzano pretty much exclusively for sauce. And make sure you buy the SM's from Italy and not the kind from California.
And I agree with Big about whole tomatoes. The less processed the fruit is the better they taste. It's real easy to break up the tomatoes yourself (first with your hands and then with a spoon as the sauce cooks).