It costs 100USD for probably 300W. If you'd want to run 300W with the Crees you'd be looking at:
4x CXB3590 CD bin 132USD
4x fans+heatsinks 50USD
1x HLG-320H-2100A 86USD
Total of 268USD, yeah I know... expensive... but WAIT! THERES MORE!
The eBay Leds (DIP @ 35lm/W) yield 105Lm/USD while the...