I am in the middle of my first grow. Started mid oct. Room is 3 by 4 and 7 feet tall, in garage, no heating, coming on to winter. I started out with LED's. My wife was on my back about power usage and my son had an led unit from college that he used, but it wasn't strong enough and he gave up... so I thought I would get another one and maybe two would do the job. I bought one from Amazon, Blackstar or Blackstone, something like that. (I know there are better ones, but even $250 was hard to justify. It was rated at 11800 lumens. I think it was $250. It was stronger than my sons. Put them both in the space on rope ratchet hangers and put in six different clones in soil (this is a legal grow, allowed six mature plants) I found the plants could grow within an inch of the light with no harmful effects. The plants were healthy and growing but it was obvious to me (novice grower so what do i know) that my plans for 12 square feet of scrog wasn't going to happen. I couldn't see how I would fill the space...Just not enough light for the space, particularly when I went into 12/12 . So I had two four foot florescent two bulb lamps so I added them to the mix. That helped, but i still felt I needed more light. Also, temps were pretty low, which is good, except my garage gets down in the 40's and the led's run cool, so I added a small space heater, a mylar lining to the poly, and used one of my home brewing thermostats to have heat come on at 60.
So, I decided to add a 400watt hps/mh. Nice product, variable wattage, i just used the hps bulb. Wow what a difference. 55,000 lumens. It also warms up the room nicely which also helps a bit on humidity. I've had the hot lamp as close as 4 inches from the plants to no ill effect. I haven't finished this grow, and heat generation is not a problem, and my wife won't see the PG&E bill so....if I had to do it all over again I would purchase two 400watt hps/mh for my situation. For my twelve square feet I now have two four foot florescents, two led panels, and one hps for a total of 83,000 lumens. I think that is finally enuf light.
I like the led's and they are holding their own, but cost wise I guess I would go hps. This has been my experience, albeit novice. I'll see if I can upload a pic. This photo is 1 week into 12/12, started to stretch, just put in some additional support for them to grow thru. Uneven growth is more about different clones than lighting.