Most do not get it that a 150w 10K usually has more par than a 250w 20K.
I did a lot of research on output as I was going to go with a dual 250W outer orbit with xm20K's. I was just as happy with phoenix bulbs so I compared the output of a 150w phoenix to a 250w xm20K and the phoenix actually had better par & I still loved the color "I do like the xm a tad better"
So overall, going to dual 150W phoenix bulbs was the smart decision for me, and will definitly show on my power bill.