Here's a comparative analogy for understanding the similarities and differences between all-wheel drive (AWD) and four-wheel drive (4WD): Miller Lite is to tequila as all-wheel drive is to four-wheel drive. Both are means to an end, but while beer and all-wheel drive are acceptable for everyday use (never at the same time, of course), tequila and four-wheel drive should be reserved for special occasions, when you need something stronger.