There are a lot of factors to consider for the "best" light.
I think individual applications can be deciding factors for "the best light". Square tanks vs long/narrow tanks, deep tanks, shallow tanks, etc etc.
I think cube tanks are best lit with MH lights. T5's are good IF they're propperly reflected. And a properly cooled fixture (not the sunlight supply fixture) can get almost DOUBLE the output (can't remember the name of that 'better' branded T5 fixture). I'm really contemplating voiding my sunlight supply warranty and carving holes in the top of my 8 bulb fixture for ventilation fans. Heard you get about a 75% increase in output by running the lights cool.
about those solaris lights, I think of them as buying your fixture, AND your next 8 bulbs at the same time. That's something I rather would NOT like to do, since it can be great to experiment with a different bulb combination when you change lights. Sure you can change the colour, but you're just decreasing output with colour changes. The good thing going for the solaris fixture though is the fancy cloud effects it's computer can do.
I was pricing out the components of the solaris for a while, and those 1-2W LED's get pretty pricey once you work in the cost of their power supplies. Not very economical to DIY...
speaking of economical, MH wins as king for costs if you understand how to solder a capacitor
