Are they worth it........to me they are
Do they make a difference.........to me they do, I like the alternative look in the evenings
Which are best.........hard to say as all will have a positive or negative side depending on tank depth and locations and what is in the tank.......as well as the actual color output of the light.......They probbaly do not make much of a difference tothe tanks inhabitants unless they are setup and timed and controlled according to a lunar schedule and the critters n the tank are dependant on that lunar schedule to take advantage of it for propagation and spawning etc, so probably for 99.99% of sw tank owners its for their own personal touch and viewing pleasure. I seem to lean towards my home brew lights or with coral lifes 3/4 or 1 watt lights myself......