LED PANEL

Its hard to say how good they are for a planted aquarium, not knowing the lumen output of the bridgelux LEDs. I would recommend using the RapidLED kits because those Cree XP-G and XP-E LEDs are some of the best and they will definitely work.

I really don't even think lumen is the major factor. An LED can be as bright as you want it to be, but if it does not put out light in the spectrum that is usable by plants, it simply won't grow plants. I've seen very few LED's provide spectral graphs the way T5's do. Until they do, it's a total shot in the dark.

with any fluorescent light, you need to be replacing the bulbs every 6-9 months to get optimal growth out of the bulbs. While the bulbs may not die for 2 years, they do not offer full spectrum for that long, and you will see a noticeable decline in plant growth after 6 months of continuous use.

Some LED solutions use less power than PC. Not all. It's completely dependent on the model. Most of the truly low power models are not suitable for plants at all. What is bright and white to the human eye often lacks the blues and reds needed for photosynthesis.

As of right now, I think the most economic option for getting good plant growth is to use twist in CFL's that are designed for plant growth, such as 6500k bulbs sold for hydroponics. No LED that I have seen can match the spectrum you'll get from them, and at $5 or less per bulb, they're hard to beat. (The new Kessil fixture looks promising, but I don't know anyone who's tested it.)

Honestly, I think you'll be disappointed if you switch from 4x96w PC to LED.

@mellowvision a fellow brooklynite? what neighborhood are you from?
Lumens are important for actually delivering the light to the tank depths I believe. If you had a light that was 6500k but only put out 10 lumens then you would have the right spectrum but you wouldn't have the light power to deliver it. I fully agree with your opinions on color spectrum at the moment. LEDs still have a ways to go before they distribute colors as efficiently as T5