Sometimes, it's quite a fraud in choosing medals or challenge coins. You should consider the end list of each one and it needs a sensible decision. As you can see, you should deal with the designs, sides, shapes, size, price and usage of medals and challenge coins because they all vary.
Medals are mostly designed the be single-sided (but can also be double sided) the reason for it is to show the public the front one to let the audience know the decisive idea of its purpose. To show firmness, it has smooth sides.
It can also be personalized to be multi-shaped. The price is more economical compared to the challenge coins and it has single side tooling charge. If you prefer dual sided medals, dual side tooling is necessary. Mostly, they are designed to be 2 to 4 inches to fully show logo or texts.
Medals have less usage in limited occasion because it is only used for awarding types of race. It is baled with a ribbon so that you can wear it.
While challenge coins are usually created to be double-sided for it to show the complexity to audiences because they can see a scheme on each sides. To emphasize the elegance of the coin, it is multi-sided with oblique or bezel edges. Traditionally, coins are round shaped and sizing 1.5 to 3 inches to easily carry it's delicacy.
It is often used on wide occasions, in awarding or commemorating parties and birthdays and it is usually packed in a box. The price is more up-scaled compared to the medals because crafts and materials are highly more costly than the one used in medals.
In choosing medals or challenge coins, you need to speculate purpose time, design, budget with your activity. Choose the best one for your activity.