How does the Lumen output of the LED-PlantBar compare to other grow lights?
Lumens and lux are measurements of how bright a light source appears to the human eye. Since the human eye is most sensitive to colors plants don't need, and least sensitive to colors plants prefer, Lumens can't be used to accurately compare the plant growing capability of grow lights. If a grow light manufacturer rates his grow light output in Lumens he's only telling you how bright his grow light will appear to you and light your room, not how well it will grow your plant.

The most accurate unit of measurement for comparing grow lights is the microEinstein, which measures how many photons of light strike an area per second. But while this is a much better way to estimate a lamp's plant growing ability than lumens or lux, it is still very difficult to directly compare two different types of grow lights. All grow lights except the LED-PlantBar emit large amounts of light plants don't use very efficiently, so including that light output in a light's plant growing measurement is misleading.

How many of your lights will I need for my plants?
That depends on the size of your plant. We generally recommend using two individual LED-PlantBars per square foot of growing space for a typical full-sun plant. Plants requiring less light, like most orchids, grow well with only one LED-PlantBar per square foot of growing space. The LED-PlantBar provides three LED clusters in an easy to mount bar.

Will your LED grow lights make my plants look gray?
Sunlight and light from indoor room lights are a mix of many colors, including green light. Plants look green because they reflect this green light. To ensure your plants will look very natural when grown under LED-PlantBars, a small amount of green light has been added to the output spectrum generated by the LED-PlantBar to bring out the natural appearance of your plants. A plant grown under LED-PlantBars will look very similar to a plant viewed under sunlight or normal room lighting.

I would like to compare LED-PlantBars to high-pressure sodium lamps. What is the micromols per square meter per second (μmol·m^-2·s^-1) of photons, or the PAR watts/square meter of each bar?
Direct comparisons are not possible since LED-PlantBars only emit those light wavelengths needed for plant growth and health. Traditional white-light-based growing lamps were originally designed to accommodate human vision and light up warehouses and factories. PAR meters are of relatively little use as a measurement of light that plants really need. The typical μMols of LED-PlantBars is: 
44.0, measured @ 18 inches distance from the middle of the bar.
See the pdf file, "Technology Comparison"

I was reading other plant light websites concerning blue/red spectrums. With HID lights, metal halides are used in vegetative growth, and high pressure sodium is used for fruiting and flowering plants; Will I need separate bars for each? These other companies recommend using 50% blue in vegetative foliage stages, then 75% red in blooming stages. Also, how many bars would be required to fill a particular room?
Our LED plant light products operates differently than traditional lighting products in regards to wavelengths. The reason you need to switch light types with traditional white lights is that the wavelengths are not properly mixed. Take sunlight for example, you only have one sunlight, and while there is some wavelength change during the year, most plants are not affected. Traditional white lights emit huge amounts of blue light and only a little bit of red. Blue is good for growing, but bad for flowering. If you are using our standard light bar, then you will want to add a little deep red for flowering. This is most easily accomplished by having a single GE Soft White 60W light in the room during flowering. The light needs only to be in the room, and not up close to the plants. As for coverage, that's something the user needs to experiment with. For full sun plants, we recommend using 8 light bars, at a distance of 24" from the plants. This setup would cover a 2½ foot by 2½ foot area. However, many of our customers have found that their plants do not need nearly this much light when using LEDtronics LED-PlantBar products. Many find that 4 light bars in the frame will cover the same 2½ × 2½ foot area just fine. Others use 8 bars per frame and hang the frame higher, thus covering more plot area.