Look for integrated components that do not need or minimize development. (Web, App and Database servers)
UI/UX: What is the LOE to adopt either your existing design or a new one? Does it support Responsive Design?
OMS: Can the OMS readily integrate with your existing backoffice ERP to enable end to end Order Management?
CMS, PCM (for catalogs) can it support the variety of attributes that your product lines have?
Integration/Extensibility: Can it access and integrate exiting DAMs or other data and image repositories? What's the LOE on the initial Master Data loads? Can it automate jobs that sync Master Data (product, pricing, etc) repositories with the platform database?
Does it come with APIs and support for Web Services in order to facilitate integration with 3rd party applications?
All this with an eye on the development LOE both within the platform and in integration.
Scalability, The Product Catalog , Business User Control , Search Easiness , Reporting and Analytics , Payment Gateways , Customization
Licensing cost, Technology, ease of integration with native development and scalabilty
Omni channel retail, Mobile commerce
Type of license, Cost of license, Technology, Pre-build integrations, Complexity, Flexibility.