Both GPT-4o (OpenAI) and Claude 3.5 Sonnet (Anthropic) are excellent. But for specific business use cases — support bots, lead qualification, document Q&A — there are meaningful differences worth knowing before you commit to an integration.
Test Setup
We ran both models on three tasks common in our client projects: (1) customer support with a 100-page help doc knowledge base, (2) lead qualification via conversation, and (3) extracting structured data from unstructured contract text.
Customer Support Accuracy
Both models scored well on RAG-augmented support. Claude 3.5 Sonnet showed slightly higher "I don't know" rates — useful for support bots where wrong answers destroy trust. GPT-4o was more likely to attempt an answer even with low-confidence retrieval.
Lead Qualification Conversation Quality
GPT-4o felt more natural and conversational. Claude 3.5 was slightly more formal but more reliable at following structured qualification scripts without going off-script. For strict qualification flows, Claude; for warm, natural conversation, GPT-4o.
Structured Data Extraction
Claude 3.5 Sonnet consistently outperformed GPT-4o on long-document extraction tasks (200+ pages). It better maintained context and produced cleaner JSON outputs. For invoice parsing, contract review, and document Q&A — Claude.
Cost Comparison (per 1M tokens)
- GPT-4o: $2.50 input / $10 output
- Claude 3.5 Sonnet: $3 input / $15 output
- For high-volume support bots (1M+ tokens/month), GPT-4o is noticeably cheaper.
Our Recommendation
Default to GPT-4o for lead qualification bots and customer-facing conversational AI. Use Claude 3.5 Sonnet for document-heavy tasks (contracts, invoices, long knowledge bases) and any workflow where hallucination is a high-stakes risk.
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