ChatGPT vs Claude vs Gemini vs Grok for Customer Support: We Benchmarked 2,535 Replies

How we ran the benchmark

We score AI models the way a customer would experience them: on realistic customer-support questions, with the answers graded blind. Across three rounds we collected 2,535 individual evaluations spanning 18 models from OpenAI (ChatGPT), Anthropic (Claude), Google (Gemini) and xAI (Grok).

Each answer is scored 0–100 on six dimensions — accuracy, relevance, completeness, helpfulness, tone and conciseness — and the overall score is a weighted composite of those. We also record end-to-end response time. The full, continuously-updated leaderboard lives on the Chaterimo AI benchmark page; this article is the written breakdown of what the numbers mean for an e-commerce support team.

The results: best AI models for customer support

Top 10 models by overall score (composite across all six dimensions). Tone and accuracy are broken out because they're the two that matter most for support, and response time because it's what your shoppers actually feel.

Scores are weighted averages across all rounds. Higher is better; response time lower is better. See the live benchmark for the current standings and methodology.

1. The race at the top is incredibly close

The five best models are separated by roughly a single point (63.1 down to 62.2). In practice that means there is no single "best AI for customer service" that towers over the rest — once you're in the top tier, the differences between ChatGPT, Claude and the leading Gemini model are smaller than the difference a good knowledge base or prompt makes. The model you pick should come down to cost, speed and tone, not a marginal point on a leaderboard.

2. You don't need the flagship — "mini" models won

The single highest overall score came from ChatGPT 5.4 mini, and ChatGPT 4.1 mini landed in the top five. These smaller models cost a fraction of the flagships and answer faster, yet matched or beat them on support quality. For a store handling thousands of conversations a month, that's the difference between an AI support bill that scales painfully and one that doesn't.

3. Claude wins on tone and empathy

If brand voice is central to your support, the numbers favour Claude: Claude Opus 4.6 (84.9) and Claude Sonnet 4.6 (84.0) topped the tone dimension. For premium brands, sensitive categories, or any store where every reply needs to sound warm and on-brand, Claude is the safe pick. We dig into the personality differences in our ChatGPT vs Claude for customer service comparison.

4. Accuracy is the ceiling for every model

The most important finding isn't who won — it's the gap everyone shares. No model scored above ~54% on factual accuracy on real support questions. That's not a knock on the models; it's the predictable result of asking a general-purpose AI about your specific products, stock, shipping times and return rules — facts it was never trained on.

This is the single most important thing to understand before deploying AI support: the model is only half the system. The other half — the half that closes that accuracy gap — is grounding the AI in your own catalog, policies and knowledge base so it answers from your real data instead of guessing. A grounded mid-tier model beats an ungrounded flagship every time.

5. Response time varies more than 10×

For live customer support, speed is part of the experience. The fastest top models replied in under 4 seconds — Gemini 3.1 Flash-Lite (~2.8 s) and ChatGPT 5.4 mini (~3.9 s) — while the slowest took far longer (Grok 4 averaged ~27.7 s, and Claude's largest model ~17.8 s). A shopper waiting for an answer mid-checkout feels every one of those seconds, which is another reason the fast, efficient models are often the better real-world choice for a storefront.

So which AI should you use for customer support?

• Best all-round value: a fast "mini" model (e.g. ChatGPT 5.4 mini) — top-tier quality, low cost, low latency.
• Best for brand voice: Claude (Opus or Sonnet) — strongest tone scores.
• Best for speed: Gemini 3.1 Flash-Lite — fastest among the top performers.
• Most important of all: whichever model you choose, ground it in your own data. That, not the model name, is what determines whether your customers get correct answers.