Anybody got any experience with mini ducts?

I just read an article and they sound like the perfect answer for existing homes that have never had ducts. Get this... 2 inch supply lines! They say the velocity is really high so there is less chance for stratification to occur. They are also easy to snake into a wall, floor or attic run. Only one size supply line and two sizes for the supply trunk!! Is this easy or what??

I am considering this for my home (old victorian) but still haven't decided... wanting to hear from some of you AC specialists.