Residential - new NM wiring.
If you're installing new wires, I would go with 0-10v, which is currently the industry standard. You'll just have to have a set of thermostat wires(two conductors) going from dimmer to every fixture for 0-10v low voltage control.
I don't like Mark X or Tu-Wire system. They wire up like incandescent, but selection is limited on dimmers and ballasts. They're not the smoothest dimming system, they're prone to buzzing noise and both the dimmer and the ballast are very expensive.($100 ea range) They're really meant for retrofit where its cost prohibitive to snake new control wires.
Everyone makes 0-10v controls in all shapes and colors and almost every ballast are available in 0-10v control. They will work flawlessly across the entire range and they do not make noise.
