Good advice Fred. Last night I was scouring the web to find the lux equivalent in LED wattage compared to a 20W Xenon bulb, and I held a bulb up inside the cabinet to get some idea how bright it might end up. When I placed one of these bulbs in the 39" wide upper cabinet, it appeared that one would not be bright enough when full power is desired, maybe two Xenon bulbs would do the trick. Then I figured each Xenon bulb's light power is roughly equivalent to 4W of LED. If I used the higher power LED strip I would use a shorter piece, only about 2 feet long. But that would defeat the purpose of the more even illumination with a full surround LED strip, so like you said the 0.9W would be much better, wrapped all the way around. By the way I always avoid blue looking lights, always go for the warmer 2700K temps. I am also seriously considering the EnvironmentalLights brand RGB + Warm White strip because I know my wife would go crazy about the ability to change mood colors along the 8 upper display cabinets, plus the ability to put it in Warm White mode for normal display. They claim a CRI of 90+ which is hard to believe. These are listed as 3W/ft. which means that it should be less than that with only the Warm White LEDs turned on. I wonder if these would be decent. http://www.environmentallights.com/led-rope-and-strip-lights/led-strip-lights/rgb-colorplus-led-strip-lights/14318-rgbww-reel-12.html

Having a photo of your installation may help us Houzzers in assisting you. A light valance is essential to reduce the glare from the light source. The colour, measured by the Kelvin Scale, of the light emitted is also a big factor in the acceptance of illumination source. Most big box home centers have displays showing light sources (bulbs) and the softness of the light. Review light sources by the lumens produced and not the wattage. The image below shows LED and incandescent lighting installed under a upper cabinet for counter top illumination.

if you're placing it under 12" deep upper cabinets the putting it at the front will give more evenly distributed task lighting over a 24" countertop. I would only install it toward the back if you have a nice backsplash that you're trying to accent. toward the middle you get a little of both

It comes in a few different ways. You can get a long roll and connectors or some brands come in 2 inch and up sizes that can connect together. I would suggest going to a good lighting store to see the options and get advice. The big box stores are more limited in what they carry and the sales reps might not be as knowledgeable.