There's so much to bare in mind when buying an LED grow light. Its not like any other light on the market where you get exactly what it says on the tin. You have to consider the quality of every component. where it was produced, the reputable supplier, but some things you can rely on are that, you save money on electric, there is a lot less heat so you can have your lights so much closer to your canopy and in turn lose less lumen. They are more universal in spectrum and cover you through veg and flower. As for best on the market it really comes down to who has the most money to produce/market these lights. Black Dog Platinum is amazing on paper. you get a good guarantee but it WILL break your piggy bank. Buy a knock off one for china and you could be wasting the few hundred dollars you spent.

Are LEDs the way forward? For the majority of growers I'd say so. As long as you have the money to spend on the initial investment. If you're growing on a scale (legally) where you don't need to worry so much about heat emissions and power consumption then stick to what you know.

There are various Youtube videos testing all the questions you're all asking. A lot of them promote LED and prove that what they put out is miles ahead of the lights we're currently using from the same measured distance above the canopy, not at a closer range which LED can sit.

The bottom line is, LED unlike all other grow lights are so varied in quality, spec' and price, they only real way to choose which LED will be best FOR YOUR PERSONAL NEEDS, is to learn how to understand what the manufacturer is putting out as a spec and whether you can afford the initial investment.

I personally have been quite happy with my led grow lights from http://www.evolutiongrowled.com/
Overall great prices and selection including everything from led grow light kits (One of the few companies that offer a complete DIY Kit!)
I actually got started in led by purchasing one of these kits http://www.evolutiongrowled.com/evolution-led-grow-light-diy-kits-and-parts.html
It was totally complete and went together pretty smoothly. I have now "graduated" to something much more sophisticated, Evolution 100 connectable led grow lights. They are like led grow light Lego's, You can physically connect lights and make any size you want! One of the reasons I chose this company is they are pretty straight forward about what to expect from your led grow light. Right from the start all of the led grow lights they sell are listed with the actual led wattage of each light! Before buying I found most companies lie about what the lights they sell will actually provide to your plants!

My Lumigrow Pro 325 units are putting out too many photons in too small of an area. I bleached the top bud on my plants because they were 16 inches away. I should have used just the old ES series in this lineup but I remember SOTF420 say he needed to keep his ES 330 two feet above his plants.

I've got my LED grow light from here. I've got a small indoor grow room with Apollo GL60LEDs and TML25 from TruLite LED. Been quite happy with the results.