I have been doing custom X-Cart development for the past five years. I find it to be a powerful cart that is easy to modify based on the smart template system. At the time of its release, X-Cart was the first PHP shopping cart. I find X-Cart to be easier when doing custom modifications to enhance shopping cart functionality compared to Magento.
X-Cart is a shopping cart made by a Russian-based company. It is among the top shopping carts based on legitimate review websites due to its powerful features at a lower resource and server cost. This has been a factor in its market share success. Another factor is that it is an open source solution but has affordable options to upgrade based on required features. The pricing will depend on the features required.
The versions available for X-Cart include free, business, multivendor and ultimate. Any store that requires and forms a product variant will require at least a paid business level license. This version contains most features that a small single store business will require. The higher level version are geared for multi-store and enterprise level features.
What X-Cart lacks is phone support partially due to the language barrier of its team members, it makes up for the fact that it supports most development requests on a paid basis. This is handled by Qualiteam, which is its in-house development team. It is comforting to know that there are available development options, as long as the budget permits.
X-Cart with its X-payments connector was one of the first carts to be PA-DSS certified, a certification that is not easily obtained. This protects the owner from liabilities from fraud transactions. These standards offer a greater level of protection for the user of the shopping cart. Any core modification in the shopping cart can nullify this compliance or certification.
A drawback to using X-Cart is that with its release of version five and up, the core file system and structure has dramatically changed. This creates a new learning curve for a developer that was used to previous versions. Another drawback is that X-cart out of the box is not as SEO friendly as other shopping carts due to its URL structure created for the store pages. Like any shopping cart, care should be taken in examining all features available against the required business model.