I bought the Blichmann burner and am happy with it.
Disadvantage
It costs twice what other burners cost
Advantages
Its *UNBELIEVEABLY* quiet compared to other burners. If you spend time near it, thats worth something every time you brew.
Supposedly it uses less fuel? Maybe it's true, I don't know, but it would take A LOT of brew sessions to save enough on Propane to break even. On the other hand running out of fuel earlier and making more trips is worth something
It's probably better made and wont rust/fall apart, where as a crappy burner might after 15 years?
It has a better wind screen, though you can make one your self.
Can support a 55 gallon pot if you need it. It might be safer to use in that it is built to support more weight than other burners. It also has attachments to prevent a pot from slipping off the side and spilling boiling wort on you. It wont slide off, but it can still be knocked off.
Bottom line - for $75 more I like it better and if I use it for 15+ years, thats a $5 per year premium, which I can afford.