Vapi vs Sierra
Zero of fourteen models named Vapi first on the direct prompt; zero named Sierra. Vapi was named by fourteen of the fourteen models and Sierra by seven and Vapi carries 39 labels and Sierra 11, so the shares are not directly comparable.
Named in one category this edition.
Named in three categories this edition.
Share is the count of first choices across the direct, paraphrase, budget and scale prompts over all fourteen models, for a mid-market B2B company; rank is within the category; every quote names the model and the prompt it came from. Both figures come from the AI voice agents page.
By framing
VapiFirst choices, of fourteen modelsSierra
Across every category in the October 2026 Edition, Vapi and Sierra were named in the same answer twenty-five times, of the 107 answers naming Vapi and the 50 naming Sierra. In those answers Sierra took the first choice three times and Vapi four.
Every model, every framing
| Model | Direct | Paraphrase | Comparative | Budget-constrained | Scale-constrained | Negative |
|---|---|---|---|---|---|---|
| Claude Haiku 4.5 | | | | |||
| GPT-5.4 mini | | | | |||
| Gemini 3.5 Flash | | | | | ||
| Perplexity Sonar | | | ||||
| Grok 4.1 Fast | | | | | | |
| Mistral Small | | | ||||
| DeepSeek V4 Flash | | | | | | |
| Llama 4 Maverick | | |||||
| Qwen 3.7 Flash | | | | |||
| Kimi K2 | | | | |||
| GLM 4.7 FlashX | | |||||
| MiniMax M2.5 | | | ||||
| GPT-6 Luna | | | | | ||
| Muse Glimmer 30B | | | | |
Vapi Sierra first choice named as an alternative argued againstblank: not namedEach cell is one answer, Vapi on the left and Sierra on the right.The direct prompt
Neither was the first choice, one was named
3 of 14 modelsThe answer put something else first and named one of the two as an alternative.Neither was named
11 of 14 modelsThe answer made no first choice from these two in this category.Bold names in an answer are the products the judge labeled a first choice; a model naming several gives each of them that label. The full answer text for every row is in the record.
By buyer segment
Sierra7%#5 of 11Vapi5%#8 of 11What the models said about Vapi
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of eight in this category shown.
“Vapi — Pricing Concerns - 55% price increase in December 2025” Kimi K2 · negative prompt · hard negative
“"API-First Only" Tools (e.g., Vapi, ElevenLabs): If you are not a developer, you should strictly avoid platforms that offer no visual builder” Qwen 3.7 Flash · negative prompt · soft negative
“it should be avoided or heavily vetted for regulated data like PHI, PCI, or GDPR-protected data without a signed Business Associate Agreement” Muse Glimmer 30B · negative prompt · soft negative
“*Developer-first / Infrastructure:* Vapi, Retell AI, Vocode, or Bland.ai. (Excellent for high customization, low latency, and BYO keys).” Gemini 3.5 Flash · scale prompt · first choice
“Choose Vapi if you want the fastest path to a production phone agent or a configurable voice-agent stack across many providers.” GPT-5.4 mini · comparative prompt · first choice
“For pure usage cost, Vapi is the lowest hosting entry point and Retell is the most quoted all-in low price with no platform fee.” Muse Glimmer 30B · budget prompt · first choice
What the models said about Sierra
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of seven in this category shown.
“Why avoid: Not suitable for mid-market buyers or those with under 100 concurrent calls.” Mistral Small · negative prompt · hard negative
“Sierra - if you have under 100 concurrent calls, no dedicated operations team, or if your budget is under $50,000 annually.” Llama 4 Maverick · negative prompt · soft negative
“Not recommended for mid-sized B2B companies unless you have a massive support volume and a large budget.” DeepSeek V4 Flash · paraphrase prompt · soft negative
“1. Sierra (Best Overall for Mid-Market B2B)” Claude Haiku 4.5 · paraphrase prompt · first choice
“Choose Sierra if you are a large enterprise brand looking for a premium, omnichannel solution” GLM 4.7 FlashX · comparative prompt · alternative
“Sierra AI is best for maximum brand governance and tone control” Claude Haiku 4.5 · comparative prompt · alternative
Comparisons are drawn for the top eight products in each category, each against each. The output is the models' output; nothing here is a recommendation by the index.