To check a data visualization service provider (https://datalance.net/data-visualization), look at their portfolio, technical skills, and the knowledge of your industry. Inquire about their data integration, dashboard customization, and support. It's also essential to understand what types of visualization tools they rely on, and whether their solutions will work well as your business grows. You can get good ideas by reading customer reviews and asking to see sample reports. Datalance, for example, is one of the companies that can be compared for its various data-related consulting products.