I use these tonight... interesting.
My other experience has been with Cento Certified (my main canned tomato) recently the Muir Glenn Organic Puree, and a while back with Nina San Marzano (Costco in #10 tin can).
Comments: The tomatoes were quite large and were indeed ripe. There were about 8 in the 28 oz can. The sauce/liquid surrounding the cans was a bit watery, and after letting drain over a strainer, I had about 50% more water that drained than I normally get with Cento Certifieds. The cans are lined with white plastic, which may be BPA-based.
Preparation: After breaking apart the fruits and letting drain for 15 minutes, I ran them through a food mill, added some kosher salt, garlic powder and olive oil and let sit for a few hours before using.
Taste: The resulting pizza sauce is less acidic than the Cento Certifieds, but less as tomato-ey and less sweet than the Muir Glen Organic puree. It was actually very good, and didn't over-power the pizza. I think I will prefer the taste of the Alessi/Vigo's over the Cento Certifieds.
Verdicit: I was not happy with the amount of liquid that drained off. I was left with about 1/3 less final sauce than an equivalent can of Cento Certifieds. However, I have experienced huge variations from can to can with the Cento's so I will give the Alessi's a few more tries (will check lot numbers on the cans to try a different lot).
I think they are a good option for those seeking San Marzano tomatoes, but even with the low price (I paid $2.99), the resultant yield, does make them a bit more expensive then the Centos. They are low in citric acid, so the tomato taste is pretty clean and not overpowering.