Find Out What The Codes Are - Make sure you have a list of all the required specs from your health, city and fire inspector to make sure that the oven you buy will meet all the requirements you will need to pass inspections.
Think About Size - Make sure the oven you are buying is the right size to fit in your commercial kitchen and the right size for the kind of cooking you will be doing. Make sure you have a plan of what size the kitchen is going to be and what appliances will go where before you buy the oven you need.
Convection Ovens
Consider Whether You Need a Convection Oven or Not - Consider the types of foods you will be cooking and whether or not you will really need a convection oven. Convection ovens are more expensive than regular ovens, so you want to make sure that you really need it before you spend the money.
Find Out About Warranty Information - Make sure when you are comparing prices that you also find out about warranty information and return policies. You don't want to end up with a lemon that you are stuck with and have to replace with your own money.
Go For Quality - Make sure you use a company that is well known for selling restaurant supplies and equipment. If you take a chance on an obscure company, you could end up regretting quality or dealing with them if you have a return.
Avoid Buying Used Convection Ovens - Unless you really know the seller, avoid buying a used oven. If you end up with any problems with it, you will likely end up having to buy a new one to replace it.