The three button suit is generally quite fancy. It seems to be very tucked and polished, since the top button, the third button, sits higher up on the chest. Where the one button and two button jackets close more around the waist, the 3-button suit creates the illusion of length because of where the top button sits on the jacket.
Indeed, there has been plenty of debate about what constitutes the right way to button a three button suit. Typically, everyone agrees that buttoning the top button alone is just wrong. Where it is acceptable for a girl’s sweater, many believe that it looks silly when a man buttons only his 
top suit jacket button. Many also agree that is it is completely fashionable to leave the bottom button open. So basically, the choices fall down to two – button both the top and middle buttons, or close only the middle button wearing the suit like a one button. Truly, it is hard to believe that there is so much discussion about how a guy buttons his suit jacket.
Another point that determines how a guy buttons his three button suit is whether or not he choses to wear the matching vest under the suit jacket. Then, it is quite acceptable and rather expected to leave all the buttons open. This way, the dress shirt, tie and vest can all be seen, which is a dapper image, indeed. Further, the material of the suit will also dictate how to close the suit. Some fabrics, for instance, bulk up and leave creases across the chest making the 3-button suit jacket look too small, as if the torso and back pieces were being pulled by the button closures to fit around the guy’s body.
Personally, I love the 3-button suit when the top and middle buttons are done up. The look is so much more elegant than a one button suit. For me, the idea of everything neat and tidy is more appealing than my shirt sticking out between the suit jacket sides. Although you can still find three button suits through various websites and of course, the higher priced designers, it seems that run of the mill stores, and off-the-rack retailers do not have as much selection. This is mostly due to cost, as it is more expensive to add another button and buttonhole.
Gino Valentino offers a large selection of three button suits in the best fabrics from around the world. Made in Italy, the suits are cut from Australian worsted or merino wools, gorgeous silks, and some are hand tailored. A newer line on the market, but one that has gained immediate popularity is the collection by comic Steve Harvey. His 3-button suit sets are fabulous with hand-pick stitching, sumptuous fabrics from Italy, double pockets, and wide-leg pants with cuffs.
Lastly, I think that the three button suit is actually fancy and elegant enough for the groom to wear for his wedding. With the right shirt and tie, the look can be rather formal. Plus, this way he doesn’t have to rent or buy a tuxedo that he will never wear again. But, he will undoubtedly find another use for his 3-button suit.