from what i know you can save probably around $100 or more per fixture if you decide to DIY depending on who you purchase the light from. some of the better premade units are by Area 51, RapidLED, BML horticulture, lumigrow, bonasiahero / hans, and Advanced. from my understanding the more watts per diode, the better results. as you can see in the discussion above, people are moving towards the COB (chips on board) design now instead of individual diodes. they seem to give you more lumens for your dollar than buying individual LEDs. check out the COBs fom bridgelux and CREE