The verdict
If you run an online store and want behaviour-driven messaging, pick Klaviyo. Its MCP server lets AI tools read reports and help create campaigns, which suits a marketing team. If you are a developer building an agent or software product where every customer connects their own Slack, Gmail or CRM, pick Pipedream Connect. Do not choose Pipedream as a workflow builder for your own team or as a marketing tool. Its old Workflows product is closing, so start such projects elsewhere. A small B2B team without a store or a developer needs neither of these today.