OpenCart also has multi-store support that lets you stay on top of different stores from a single interface. This functionality lets you set products for different stores, use specific themes for each online store, and localise your websites. Product options and attributes are also quite flexible with OpenCart, and the solution lets you add extra product variables.
BigCommerce is most easily compared to Shopify. Both platforms offer a similar experience when building an ecommerce platform. Like Shopify, BigCommerce offers a range of prices and packages tailored to different types of businesses. The platform is highly customizable if you are comfortable with some light coding. It is also possible to use themes and templates to build your website, but some of these will come at an additional cost.