As for voltage, it really depends the CPU you purchase to a point. The new Intel chips need to have RAM voltage of 1.65V or less, so for them lower is better to give your overclocking room with voltage increases. As for AMD, it is really an issue, as they don't have that requirement.
As for today's market, it pretty standard to be looking for DDR3 at 1.65V or less with 1.5V being ideal, as motherboards default to 1.5V.
As for the latency... the article holds true that lower is better but in the "real world", there is little noticeable difference.