Single 250w bulb should be plenty, and for what it's worth, I think you'll be hard pressed to find someone who has been the hobby a long time that will say that LEDs look better than metal halide. It's kind of a loaded statement, because different bulbs have very different colorations, but I think that anyone who has seen a 20k radium in person, 12k reeflux, or a 10k XM with UV supplements can say that there is nothing better.
The nice thing about LEDs (and T5s, to a lesser extent these days) is that they're much more efficient (heat and electricity), and the colors are much more customizable (each bulb can be slightly modified in spectrum quality with LEDs, with T5 you can change out single bulbs to get a mix you like).
And if you're a real baller, 20k 400w radium will give you monster growth and coloration.