Who each platform is really for
Salesforce
Salesforce is the reference point for enterprise CRM: a large platform with deep customisation, an extensive partner network and an app ecosystem that can satisfy almost any requirement given time and budget. It suits organisations with complex processes, dedicated administrators and an appetite for a configuration programme.
SugarCRM
SugarCRM competes for similar mid-market and enterprise buyers, and has long been associated with greater flexibility in how the system is deployed and licensed. Editions and deployment options have changed over the years across this whole category, so confirm what each vendor supports today in their current documentation rather than assuming what was true a few years ago.