metal halide is better than HPS for vegging. I run a F54T5HO four lamp for veg and bloom using two different lamp colors. At the moment I'm using the veg lamps with HPS to flower my plants. My personal opinion based on my experience is that watt for watt MH and T5HO are equally good for vegging. With my T5 I can start with less watts (216w), my HID lights are 400w. Once the plants are established, say week three, I think they can use more light so I go to the 400w MH. Is that clear?