Alloy wheels are the most commonly sold sets in that they are built to resist and the easiest to tune. They are also the wheels that come with an entry level bike and that you may have had for ages if you have been riding for a few years. Most alloy wheels also have shallow rims, meaning that in case of a flat, a tube with any valve length will fit. An alloy wheelset is also the cheaper to make – you can mix and match any rim with any type of spoke or bearings – and naturally cheaper for the customer. The general idea that an alloy wheel is a “slower” wheel comes from the fact most lack the aerodynamics and lightweight most carbon wheels offer.
Carbon wheelsets are thus usually lighter in weight and more aerodynamic, mostly from the deeper rim depth. Carbon wheelsets are not as easy to service or produce and instead of mix and matching spokes and bearings, these wheels are composites that are molded into a wheel’s form. This also comes with a disadvantage since replacing and repairing broken parts of these wheels is not as easy (and sometimes not even doable). However, when you are looking to “upgrade” anything on your bike, you are obviously looking to become faster. In those regards, carbon wheels will help you become a faster cyclist on the road. The process of molding carbon into a wheel’s shape is something that is still more expensive than putting together an alloy wheel.
At the end of the day, it’s obviously a decision between what kind of rider are you and the purpose of your new purchase. Wheels are a strong component of your riding and they change the dynamics of the riding and the bike itself. They are also “better looking” and for some reason a better looking bike will make you more confident and strong on the ride, somewhat a placebo effect that we see often with other things in life. That itself can be worth the extra buck carbon wheels usually cost over their alloy friend. If you are a casual cyclist and are looking for an all-around wheelset to beat down to the ground in training, alloy wheels are a good choice. With carbon you might get a more fast and aggressive type of riding as they are also more stiff and responsive. The extra deep rims of most carbon wheelsets are more aerodynamic and also more susceptible to crosswinds which may require some extra bike handling skills.
Vision’s Metron wheel line is developed with crosswinds in mind, because rarely does a rider ever ride in a complete head wind. The Metron wheels are built to be very stable in high cross winds. This is achieved by transferring most of the side force to center of the wheel by using the rim’s aerodynamic profile which eliminates the twitchy feeling you might encounter on a day with high cross winds.