Sierra vs Yellow.ai Comparison

Why choose Sierra

• Higher Support score (8/10 vs 4/10)
• Higher Output Quality score (9/10 vs 6/10)
• Better fit for financial services (8/10 vs 6/10)

Why choose Yellow.ai

• Has a free plan (Sierra does not)
• Higher Cost score (3/10 vs 2/10)
• Better fit for small business (3/10 vs 1/10)

Sierra

Pros

• Outcome-based billing means customers usually pay only for resolved conversations or other agreed results, not for each seat.
• Three build options cover both CX teams and engineers: the no-code Agent Studio, the code-first Agent SDK, and Ghostwriter for building agents from SOPs.
• One agent runs across chat, voice, SMS, WhatsApp, email and ChatGPT, keeping context between channels.
• Its list of compliance attestations is broad, covering SOC 2, ISO 27001, ISO 42001, HIPAA, PCI DSS and FedRAMP.
• It has a strong roster of enterprise customers, including SiriusXM, ADT, Rocket Mortgage and SoFi.

Cons

• There is no public pricing, and competitor estimates put annual contracts at about $150,000 or more.
• There is no self-serve or trial tier, so small teams cannot try it on their own.
• Implementation is largely vendor-led, which can make customers depend on Sierra's team for changes.
• There are few public reviews (7 on Gartner Peer Insights) to verify claims against.
• Some reviewers say voice quality still falls short of human level, and that complex telephony setups depend on how far the integration goes.

Yellow.ai

Pros

• More than 35 channels, and context carries over when a customer switches channel.
• A broad security portfolio (SOC 2 Type II, ISO 27001 and 27701, HIPAA, PCI-DSS) with data hosting in the US, EU and Asia.
• More than 150 pre-built connectors, including Salesforce, Zendesk, Genesys and NICE.
• Covers both customer-facing and employee-facing automation on one platform.
• A free plan with self-serve signup lets teams test the builder before talking to sales.

Cons

• No public price between the free plan and the quote-only Enterprise plan. Marketplace listings suggest about $10,000 a year as the floor.
• Reviewers report bots losing context and missing intents.
• Support complaints centre on poor communication and account-team turnover.
• Implementations can stall, and changing live journeys often needs engineering help.
• The December 2025 layoffs and the pending SPAC listing raise questions about continuity on multi-year contracts.