I personally haven't tried these. but have talked to people who have and at $20 a bulb for single or double end MH I'm going to try them next time I need bulbs. http://www.lightexports.com/servlet/StoreFront
I agree on this, i have tried all of these Plusrites. IME, the 10K is good for growth. 14K is a balance of 10 and 20. And 20K is just color, PAR is horrible. Wiz.