Hi NDM1952,
I didn't see HydroGrow's 360W unit, but the dollar-per-watt ($6.17) figure seems kind of high,especially for larger grow lights, which should cost much less due to economy of scale (more LEDs purchased = less cost per watt). Coverage is a function of simple trigonometry - with 90 degree lenses, mounted at 24", the coverage area should be 4' a diameter, PLUS the width of the light itself. Yield (harvest) is a function of delivered and
usable photons. Almost all plants use photons in the Chlorophyll A and B absorption freqs, as well as the beta Carotene (yellows) range, and several protein accessory pigments that assist greatly in the Chlorophyll processes. A lot of these frequencies are missing in the spectrum charts I see on the "big boy's" web sites.
As for being made in China, I agree that one needs to be careful, but I also know that almost all LED grow lights have roots in China. However, there are several great manufacturers in China and if the LEDs are from top-notch companies and engineering and QC is done by the American (or insert your preferred country here) company and a good, solid warranty is offered, the risk is minimal. A sad state of affairs in the USA is that manufacture of many items we take for granted would not be affordable if we didn't get it from offshore. Also, don't be fooled about what is and what isn't made in the USA. Look and see if any of these seem familiar (then compare them to the lights you are reviewing):
http://ledstar-lighting.com/en/Prclass.asp
http://www.mkgrow.com/
http://vanqled.com/ledgrowlight/index_xx.asp?id=640
http://evergrowlighting.com/
http://www.ledgrowlights.cn/
You want to see hundreds more? Go to alibaba.com and search on "LED Grow Lights".
I am a fan of full spectrum grow lights, as you might tell from the first paragraph. I know that Black Dog (
http://www.blackdogled.com/) and Super Grow LED (
http://www.supergrowled.com/) put out full spectrum lighting. Super Grow deals in smaller units than Black Dog, but I know Super Grow has a 225W model ready for release, using the same spectrum as their smaller units. The purchase price is under $3/W for either manufacturer. Two of these larger units exceeds the total photon delivery of the units you are considering, at about 2/3 the price of your aforementioned deal for your entire grow. It would be worth it to give either manufacturer a call and ask them to cut you a deal on such a large order. I'm sure you could find a use for the money you would save.
Just my nickel's worth!