We bought a Boss blower this summer, and have been pleased with it so far. I think it's true advantage might be most apparent during the winter months. Our decision to buy the Boss was based mostly on 2 factors: the (hopefully) greater longevity, and similar performance to the 2 blowers / cart set-up with a whole lot less equipment to haul. The Boss will not produce the air volume of the 2 blower set-up, BUT, it is a whole lot easier to handle - particularly for our 10 year-old daughter. The single hose with 2 blowers is pretty big for a small hand! We still have our cart, etc, for the double blower set-up, but no one wants to use it...everyone prefers the Boss. If you add the cost of 2 blowers, cart, "y" hose, etc together, the cost of the Boss looks a little more "reasonable." I would suggest that you have a good power source, and use heavy cords with the Boss, but it still takes less power than 2 regular blowers combined.
Time will tell if it was a good investment... but as our 2 daughters say, "It sure does look cool!"