Shopify is better suited for eCommerce businesses that primarily sell online and require advanced inventory and shipping capabilities, as well as powerful website-building features and extensive integrations. In contrast, Square is more suitable for brick-and-mortar businesses that rely on in-person sales, offering simplicity, advanced POS hardware, and specialized POS systems for specific types of businesses. Both platforms offer robust analytics, marketing options, and customer management tools, but their pricing models differ, with Shopify charging a monthly fee to access features and Square offering a free plan with limited capabilities. Ultimately, the choice between Shopify and Square depends on the business's primary sales channel and its needs for eCommerce or in-store POS functionality.