"I guess I was wondering if quality modern snow tires like the Blizzaks are better than chains,"
They're much more convienent when the traction is ok for the conditions, but that doesn't matter when the traction isn't ok. From what I've experienced so far the lighter the vehicle and the colder the temps, the better they'll work on snow, packed snow, and ice. A vehicle weight increases you start finding that traction varies a lot more in different conditions. At lower temperatures the ice is hard, where even decent all season tires can do well at slower speeds. In deeper snow you may need an aggressive tire or chains. As the temps get closer to freezing the snow can get slushy, where more aggressive tires, studded tires or chains may be needed, and the ice gets soft as well as developing a water film under pressure. Note that most claims for as good or better performance than studded tires seem to have originated with tests done on hockey rinks, which has hard ice, while other more comprehensive tests under different conditions find that studded tires do best on 'soft ice'.
Whne the conditions are bad enough around here it's chains only, regardless of vehicle or tires. Another consideration is ice racing, where there are different classes for the custom spiked tires, where roll cages and such are needed due to the speeds encountered, a class for regular studded tires, and one for studless tires. The studless class ends up with the lowest speeds.
I bought some Michelin Artic Alpins a few seasons ago to try out some of the studless tires, and they don't work as well on soft ice as studded tires, or more agressive snow tires with bigger lugs in deeper snow. Siped, studded, heavier lugged snow tires work best for me, but I still carry chains too.