It's a qualified "Thumbs Down".

After using the LED lights for about a week, I've decided to consolidate all
into a single bed as supplemental lighting only.

The basic problem with these 50W 12"x12" LED panels is they basically light
one sq ft of plant area. The light is a tight beam, and no matter how much
light they put out, you can't practically replace an HPS light with a 50W
panel (unless your garden is 1 sq ft).

Now 8 of these on an 8 sq ft bed would probably kick butt, but the costs are
too high and the wattage is the same as the 400W HPS they replace. Then
the only advantages are lower heat generation and better spectrum.

I'll move the 3 panels I got to the small veg bed, where the small light
area is not such a problem, and augment with HPS to cover the fringe area.

Right now those 50W panels

http://www.htgsupply.com/viewproduct.asp?productID=53194

are about $130US apiece (with tax), so they are too high right now. When
they drop to about $50 each, I think they'd be worth it, but not until
then. They could also change to an LED with a better spread angle, say 30
deg or so. I'll keep watching, because I still have hopes for this
technology, but I can't recommend it yet.

-mikey