the lumens isnt as important as some people think its only a measure of how strong the light is to the human eye,anyway ive kept some big buds under 400w cfls and they look far less dense than the 1''s under the plasma also the plasma 1's produce alot less leaf and stalk it promotes alot more bud, the penetration is really good through to the bottom of the plant, it cost me around £800 for a 730w but the light output is the equivelant to four 400w hid's, plus the bulb lasts 10 years and only depreciates 5% in the first 20 mins of its life and so it stays at 95% effectiveness throughout therefor saving you around £120 a year on bulbs avg. loads of electricity a massive difference in the bill.........you keep the light the same as you would a HID, 1 light covers a 9ft circle, it puts out about the equivelant heat of 2 cfl's which is nothing, the 1 i have is 6000k very similar to the sun budding resonds very well and the best thing is no stretching occurs , the 1 i have is a 90 degree angle but u can get 120 i rate these very highly and so does my mate who is very experinced has been growing for over 20 years, the noise is 36'd' , it weighs 19k and is the size of a 17 inch crt tv, i will post some pics tomoz to show you the difference