From a wheel-builder's perspective, it's pretty easy to tell the difference. Straight-gauge spokes tend to be spongy, and they also tend to build tension up slowly and somewhat unpredictably. This matters less when spoke counts per wheel are high. DB spokes build up tension a lot more quickly and in linear fashion. Triple-butted spokes are a must-have IMO for the drive-side rear, as they have to take more tension (due to the dish). The biggest disadvantage for DB spokes is in wind-up for the thinner gauges.