You should choose a wholesaler based on their range and prices, and how well they could meet your needs. Don’t worry about whether your competitor has made the same decision: a good wholesaler will have many customers.
In many cases, in fact, the base price of products and materials might not vary much at the wholesale level, so there may be little financial impact in switching suppliers. However, if you find you’re buying the same wholesale products as your competitor, and selling them at the same mark-up, you do need to think about how you can differentiate your business.
Consider expanding your range, adding value and improving your customer experience.