AI vendor comparison · 2026

ChatGPT vs. Claude vs. Gemini vs. Copilot vs. KOSMO – which AI fits your company?

Short answer: it depends on the use case – not on the brand name.

For general office tasks with internal data, Microsoft 365 Copilot is the obvious choice for many. For client, patient and customer data, KOSMO is the only vendor in this comparison that is GDPR-compliant and viable on-premise. ChatGPT, Claude and Gemini shine in private use and prototyping – with personal data they do not belong in business operations.

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ChatGPTOpenAI · USA
ClaudeAnthropic · USA
GeminiGoogle · USA
CopilotMicrosoft · USA
KOSMOSplitbot · DE
The overview

AI vendors compared directly

Eight criteria, five vendors – at a glance. Detailed profiles are in the cards below.

Criterion ChatGPTOpenAI ClaudeAnthropic GeminiGoogle M365 CopilotMicrosoft KOSMOSplitbot
Hosting location USA USA (AWS) Google Cloud US EU optional DE on-prem / EU cloud
DPA in the standard plan ✕ Enterprise only ✕ Team & Enterprise ✕ Workspace EA ✓ M365 EA included ✓ Standard
No training on inputs ✕ Free/Plus no, Enterprise yes ✓ No training by default ~ Workspace yes, consumer no ✓ M365 yes, guaranteed ✓ Contractually excluded
GDPR-compliant for customer data ✕ ✕ ✕ ~ with Enterprise setup ✓
Available on-premise ✕ ✕ ✕ ✕ ✓
Suitable for § 203 StGB professions ✕ ✕ ✕ ✕ ✓
Subject to the US CLOUD Act ✕ Yes ✕ Yes ✕ Yes ✕ Yes ✓ No
Price (entry-level business) from 0 € / Plus 23 € from 0 € / Pro 18 € from 0 € / Advanced 22 € from 30 €/user/month from 20 €/user/month

As of May 2026. Prices are net of VAT, referring to entry-level business plans, and change regularly. Feature scope and conditions may vary by region and contract – please verify with the vendor.

Vendor profiles

Strengths and weaknesses in detail

Every vendor has something they do well – and things where they are structurally limited. A sober assessment.

ChatGPT OpenAI · USA

OpenAI's market leader. The largest ecosystem, richest API, many plugins and GPTs. Strong as a generalist, multimodal with vision, voice and image generation.

Strengths

  • Largest ecosystem with plugins and Custom GPTs
  • Rich API for developers and integrations
  • Multimodal: text, image, audio, code

Weaknesses

  • Free and Plus plans without DPA, with training on inputs
  • US corporation – CLOUD Act and Schrems II apply
  • Standard not GDPR-compliant for customer data
Best for: Private users, prototyping, brainstorming – with non-personal data.

Claude Anthropic · USA

Anthropic's language model, focused on cautious, coherent outputs and a very long context window. Strong in reasoning and long-document processing.

Strengths

  • Very long context window (200k+ tokens)
  • Strong in reasoning and long documents
  • More cautious answers thanks to Constitutional AI

Weaknesses

  • US corporation – CLOUD Act applies
  • Free plan without DPA
  • Smaller plugin and tool ecosystem
Best for: Long document analysis, coding, research and editing – with non-personal data.

Gemini Google · USA

Google's language model, closely tied to Workspace and Google Search. Strong in multimodality and real-time web access.

Strengths

  • Full multimodality: image, video, audio
  • Deep Workspace and search integration
  • Real-time web access via Google Search

Weaknesses

  • US corporation – CLOUD Act applies
  • German language polish sometimes weaker than ChatGPT/Claude
  • Forces a tight Google ecosystem
Best for: Workspace customers, image analysis, web research – with non-personal data.

Microsoft 365 Copilot Microsoft · USA

Microsoft's AI assistant, deeply integrated into Microsoft 365. With EU Data Boundary, data processing agreement and contractual training exclusion – the most serious cloud candidate for business.

Strengths

  • Deep M365 integration: Word, Excel, Teams, Outlook
  • EU Data Boundary configurable
  • No training on tenant content (contractual)

Weaknesses

  • US CLOUD Act applies despite EU hosting
  • Bing Grounding sends data out of the tenant
  • Not sufficient for § 203 StGB professions
Best for: M365 customers with an Enterprise Agreement, general office tasks with internal data use.

KOSMO Splitbot · Lübeck (DE)

Splitbot's GDPR-compliant AI assistant. Runs on-premise or in sovereign EU data centres – no US cloud, no third-country transfer, RAG on your own knowledge sources.

Strengths

  • On-premise or sovereign EU hosting – no US cloud
  • RAG with your own data, multi-tenant
  • Suitable for § 203 StGB professions and special category data

Weaknesses

  • Smaller plugin ecosystem than US vendors
  • On-premise requires your own hardware – higher entry barrier
  • Specialised for the DACH and EU market
Best for: Law firms, healthcare, public bodies, SMEs – everywhere personal data or professional secrecy is involved.
Decision aid

Which AI for which use case?

Six typical scenarios from business practice – with a concrete recommendation and short rationale.

General office tasks
Recommendation: Microsoft 365 Copilot

Anyone already using M365 gets Word, Excel and Outlook context directly in the prompt. With an Enterprise Agreement and EU Data Boundary, Copilot is viable for internal company data.

Processing customer data
Recommendation: KOSMO

Once personal data flows into the prompt, on-premise or sovereign EU hosting is the only cleanly GDPR-compliant option. No US cloud, no third-country transfer.

Coding and software development
Recommendation: Claude or ChatGPT

Both have strong coding models and large knowledge bases. Important: no production source code with business logic or credentials in the prompts – otherwise KOSMO with code RAG.

Long document analysis
Recommendation: Claude or KOSMO

Claude has the longest context window and understands entire contracts at once. As soon as the documents are personal, the analysis belongs in KOSMO – e.g. with RAG on your own document collection.

§ 203 StGB professions (doctors, lawyers, tax advisors)
Recommendation: KOSMO

Professional secrecy does not permit third-country transfer. Even Copilot Enterprise is not sufficient here, because Microsoft as a US corporation is subject to the CLOUD Act. On-premise is the only clean path.

Brainstorming and marketing
Recommendation: ChatGPT or Claude

If no personal data is involved, the market leaders are pragmatic enough. For German headlines and language polish lean towards Claude, for creative concepts and image generation lean towards ChatGPT.

Frequently asked

FAQ – the most common comparison questions

There is no winner that takes every category. ChatGPT has the largest ecosystem, Claude the best reasoning, Gemini the strongest multimodality, Copilot the deepest M365 integration, KOSMO the best GDPR position. Which one fits you depends on the use case and data class – not on the brand name.

Sources & further reading

This page draws on the following public sources and vendor documents:

Related topics on Splitbot.ai

ChatGPT & DSGVO
Detailed GDPR analysis of ChatGPT, Claude and Gemini
Copilot & DSGVO
Detailed GDPR analysis of Microsoft 365 Copilot
On-Premise KI
How KOSMO is deployed on-premise
KOSMO Preise
Transparent KOSMO pricing at a glance

Which AI fits you? Talk to us.

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This page provides a factual overview as of May 2026 and is not a substitute for legal or purchasing advice. Vendor feature scope, prices and contractual terms change regularly – please verify with the vendor.

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