For cooking Italian sauces, especially when tomatoes are not in season, the canned whole peeled tomato in its juices, is the best way to go.
Short of having perfectly ripe plum tomatoes in the summer, the canned way is the best. The San Marzano imports or the San Marzano or plum varieties grown here in the States are the best varieties to buy. Make sure they are plum tomatoes and they are meaty and sweet to the taste. Crush them with your hands or with a vegetable mill, then proceed to make the sauce. I myself do not like the pre crushed tomatoes or tomato chunks in puree. Get in the habit of tasting the tomatoes as soon as you open the can and you will be able to tell which ones you like best, then stick to that brand. Keep in mind that tomatoes are packed seasonally and may vary from year to year, from the same packer.