In my current line of work I am often responsible for order various parts from vendors. The first thing that I look for when selecting a vendor (assuming we already have an account & are able to order from them based on company SOPs) is the quality of the company that makes the part. Next, I look at the price of the part from 3 separate companies. Finally, I evaluate the amount of time it will take to actually receive the part.

There has been issues where the company takes the order, however, they did not actually have the part in stock. In this case, I check on an alternate vendor and order through them if the part will come in sooner.