The main difference to consider when selecting a pizza peel is whether you want one with an aluminum blade or one made entirely of wood. The aluminum peels tend to be a bit lighter and more flexible, so they are easier to handle. However, with all things metal the blades could bend and potentially scratch the inside of your oven.
Pizza peels made entirely of wood are the more traditional approach. Plus, wood is more attractive than metal. Aesthetics aside, wood peels have slightly tapered blade sides to make it easier to slide under the pizza. Over time, the wood will begin to absorb some of the pizza flavor and can potentially create a taste that is unique to your establishment.