I must be the only one who isn't so convinced by DDM. I've gone through several different HID kits and am currently on a DDM set (55w 5000k hi/lo with 35w 3000k fogs) in my Altima and have had nothing but trouble out them. It might be because I'm using 55w, though... not sure.
Since installing the DDMs (hi/lo kit, relay included) I cannot turn my headlights on if I've cranked up the car already (fogs work fine), or they will flash on, then turn right back off. Also, the bulbs shake on high beams (but are perfect on low beams). I don't know where exactly the issue lies, but I've certainly not been impressed with their performance.
They do, however, seem to have the most rugged and yet slimine design of all of the sets that I've tried.