BTB, I have used all of those products. Here is the run down.
Saporito Super Heavy Pizza Sauce. This stuff is the thickest tomato paste you have ever encountered. Probably twice as thick as anything you can buy in the grocery store. When thinned down its a similar flavor to a 6 in 1, but with less magic going on, and a totally smooth consistency. I like to use this to thicken other products that are too thin out of the can.
Saporito Super Sweet and Super Heavy Pizza Sauce. Stanislaus (the brand) basically has two types of products that they just form into varying thickness and consistencies. The two sides of the product line are made from slightly different processes and types of tomato. This product is the "other" version of the above product, and is exactly what you would think. It doesn't have sugar added, but it tastes like it does. It is a very sweet flavor, maybe too bright for most people. It is VERY thick like the above product. There is a sister product called Super Dolce
Full Red Pizza Sauce with basil. This is yet another Stanislaus product, but this, like the 6 in 1's is in a ready to use consistency. You will probably find no need to thin it or thicken it. Again, this is a smilar flavor to the 6 in 1, but without any chunky texture to it. Basically a puree of 6 in 1 if you can imagine that. This product is very popular for your standard NY pizza style. I find it to taste a bit better than a thinned down Saporito Super Heavy Pizza Sauce, but it is similar.
San Benito Selecto Super Heavy Pizza Sauce wbasil. San Benito is a different brand than all the other products you are asking about (which are made by Stanislaus). It is a little cheaper, and I find it slightly inferior. If Stanislaus and Escalon brands get a grade A, Sasn Benito products get a B+. The San Benito line of products very closely mimics the product line of Stanislaus. This is their version of The Saporito Super Heavy Pizza Sauce, so its basically an incredibly thick tomato paste.
Super Dolce Pizza Sauce. This is the extra sweet version of the Full Red Pizza Sauce w.basil. Similar consistency to the Full Red, so it is ready to use on a pizza without any need to add too much water or thickener. Like the Saporito Super Sweet and Super Heavy Pizza Sauce, it is a bit too sweet for my tastes.