Fixed color temp will get you more light output at the same rated wattage. In bi-colors, half the leds are daylight and half are tungsten. So if you're at either daylight or tungsten, you're only getting half the potential light output. Even if all the led lights were going, fresnels would most likely offer superior light output, since there is a big reflector behind the lamp.
Also fresnels offer much more controllable light. You can go from zoom to spot, whereas with panels, you're at a fixed, often wide, beam angle.