They are slightly less in total cost. LEDs are more efficient. The lights are usually compare to HID lighting. They do not run as hot as HID. Very efficient when used in warehouses. I am in the process of getting a 400W induction sample, can't wait to try it.
Bulbs are designed to operate correctly in different positions... (i.e. B/U = Base Up, B/D = base down, HOR = horizontal. Most bulbs are rated @ 10,000 hours. So, if you put a lamps that are rated HOR and the lamp is installed base up it will decrease life expectancy. Good luck on warranty of...
Or you could get 6 lamp 2x4 hi-bay T-8 fixtures for @ $175.00 each. The lights have reflectors are patented for 95% reflectance. This would cut down on heat.
I will not use the digital ones. I have more issues with them. Mechanical is tried and true. I am an electrician. This comes in handy when you want to make things to better your gardens.