Bikers don't wear motorcycle vests to be fancy, they wear them because they're functional. An extra layer of warmth, a few extra pockets, and a look that says, "I'm a rider - don't mess with me". Also they protect against the cement or asphalt if they get flung from the bike. And you might add that the rugged good looks of a well-made biker vest are a nice side benefit. There are also many styles to choose from, some button, some zip, so do both. Then you have lace up the sides and some even offer gun pockets on the inside.
You can get them in different colors, although I personally think black looks best. On hot days they are a heck of a lot cooler than a leather jacket. For the couples who like to match there are many different styles for the ladies as well. Leather vests make a great canvas for adding all of your embroidered patches to give it a more personalized look. Have fun out there and ride safe.
