at the end of the day the person still pays it off, its not free money.. you borrowed to do it and there was a cost.
on a investement point of view, depending on where you are in the housing cycle etc it can be profitable, but when at the top of the cycle like i belive we are now i see little point in starting one up now, I'd rather rate for a correction and the economy to get worse.
I dont think the boom of the 90's will be seen again, it will just be like the 70's and 80's once it dies down..