Help with creating a DIY low voltage garden pathway light?
Timer controlled low voltage with LED lamps is the way to go, one reason is that the inevitable failure of "line voltage" temporary extension cords could lead to shock injury. 

I agree that the consumer grade "big-box" stuff is junk and not likely to last more than 2 years without constant attention. What you need is heavy duty professional grade equipment, check with your local landscape supply house. I like this type because they are heavy duty and manufactured in my area of the good ol USA.