Which AI? · Cheat Sheet

Which AI should you use?

The best model for 14 everyday tasks, judged on results per dollar. October 2026.

Claude8 wins

Gemini3 wins

ChatGPT2 wins

Muse1 win

Copilot0 wins

Grok0 wins

Coding

Quick code checkDebug / syntax / review

ClaudeSonnet 5.5

Free on claude.ai and close to Opus at coding.

Full app buildMulti-file, architecture

ClaudeOpus 5.5

#1 on the Artificial Analysis index, and cheaper per task than Sonnet.

Full web buildHTML / CSS / JS / layout

ClaudeOpus 5.5

#1 on LMArena's WebDev board.

Writing

Quick social postsShort copy, captions

MuseSpark 1.3

Free, and built into Instagram and Facebook.

Long-form blog1,000 to 3,000+ words

ClaudeOpus 5.5

Holds your voice across thousands of words.

Research & Strategy

Article researchSources, fact-finding

Gemini4 Argon

The fewest made-up answers of any flagship, with Google Search built in.

Prompt engineeringBuild prompts for AI tools

ClaudeSonnet 5.5

Free, and second only to Opus on Artificial Analysis.

Strategic planningDecisions, proposals

ClaudeOpus 5.5

Tops GDPval-AA and the Vals Index on real business work.

Everyday Tasks

Email draftingClient, internal, outreach

ClaudeHaiku 5.5

Same price as GPT-6 Luna, and it scores higher.

Data analysisCSV, metrics, patterns

Gemini4 Argon

Keeps track of very large files and rarely makes things up.

Document summaryPDFs, contracts, reports

ChatGPTGPT-6 Sol

The lowest hallucination rate on Vectara's summary test.

BrainstormingIdeas, concepts, angles

ChatGPTGPT-6 Luna

Fast, varied, and free.

SEO & metadataTitles, meta, alt text

ClaudeHaiku 5.5

$0.10 in, $0.50 out per million tokens.

Automation workflowsAPIs, tools, logic chains

Gemini4 Argon

#1 on Artificial Analysis's business-automation test.

Claude Free (Sonnet 5.5) · Pro $20 · Haiku 5.5 $0.10/$0.50 · Opus 5.5 $4/$20 ChatGPT Free / Go $8 (Luna) · Plus $20 (Sol) · Pro $100+ (Astra) Gemini AI Plus $4.99 · AI Pro $19.99 (Argon) · Argon $2/$10 intro Copilot Free · M365 Personal $9.99 · Premium $19.99 Grok 4.7 $2/$6 · X Subscription from $8 Muse Spark 1.3 free in Meta AI · Wonder from $20

Strong free tiers from Claude, ChatGPT, and Muse. Pay when the job is hard.

WHICH-AI · The AI Vaults · October 2026