The difference in sound quality is not really anything to speak of. You cant hear a difference between ohm loads by ear.

The statement you heard is just a generalization. You get the better, louder lows because you see more power running it at .5ohms compared to 1 ohm. I really wouldnt bother with .5ohm for a daily driver setup. Much cheaper to just buy an amp that does the power you need at 2 ohms, compared to buying an amp and a ton of eletrical upgrades to support a .5ohm system.

Only reason people run .5ohms is because the lower the ohm load, the more power. Same reason people run 18v to their amps.... More power.