Installed 30 of the 15W DL9-1400's 3 years ago now in all the key rooms of the house, and 10 cheaper 12W Chinese imports into the hallway and laundry. The DL9's haven't missed a beat in the 3 years, but I have already had to replace one of the imports.
Also Wattsaver are one of the few sources that I have found with a 4500K color temp (Natural White). It is the perfect color temp for home and the brightness vs. the Halogens is night and day and I won't never go back (it is like replacing 40W bulbs with 100W ones and actually being able to see things). The money spent for all the LED lights in the house have met their ROI of <3years (yes I have been tracking the power bills from the 50W halogens to the 15W LEDs).

Approximate cost: $1600