Reviewers mostly praise Cal.com for a clean, simple interface, easy setup, and smoother scheduling than Calendly and similar tools. Repeated strengths include strong calendar integrations, support for multiple calendars and time zones, embedding on websites, and flexible customization through self-hosting and an open API. A few users also call out helpful support and built-in video calls. The main complaints are inconsistent support, gaps in Microsoft integration, downtime, and confusion over which features are truly open source, with one reviewer strongly criticizing feature paywalling.