X-Cart is an eCommerce platform that is used to create an online store. X-Cart is available both as a downloadable self-hosted licensed software and as a cloud-based cart, hosted by X-Cart team, yet with your full access to the code for customisations. It supports tons of eCommerce features either out of the box or as a ready-made extension. Installing a new module does not require technical knowledge or access to the server: the marketplace is App Store - like, right within the admin backend of the store. X-Cart offers 24/7 technical support. Besides, you can get a full stack of services directly from the software vendor: custom development, web design, eCommerce hosting and SSL certificates.
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.