Short verdict
Choose Zendesk Sell when Zendesk ecosystem fit is central to the business. Choose HubSpot CRM when you want a stronger general-purpose CRM platform for growth, reporting and broader commercial use.
Pricing considerations
Zendesk Sell is easiest to justify when it sits inside an existing Zendesk stack. HubSpot can start cheaply, but the business should still model the later cost curve if commercial complexity expands significantly.
Ease of use comparison
HubSpot is usually easier to justify for broad commercial adoption. Zendesk Sell becomes easier to defend when the team already works across Zendesk workflows and values that continuity.
Implementation and migration comparison
HubSpot is generally the lighter migration destination for a broad SMB CRM rollout. Zendesk Sell is more compelling when implementation can reuse an existing Zendesk ecosystem rather than starting from scratch.
UK small business suitability
HubSpot is the broader fit for UK B2B and service-led SMBs. Zendesk Sell is stronger for UK businesses where support, service and sales context already live together inside Zendesk.