Compare Horizon Beta by OpenRouter against xAI: Grok 4 by xAI, in 9 community votes, horizon beta wins 88% of head-to-head duels, context windows of 256K vs 256K, tested across 40 shared challenges. Updated April 2026.
Horizon Beta is the better choice overall, winning 88% of 9 blind community votes on Rival. Horizon Beta costs $0/M input tokens vs $3/M for xAI: Grok 4. Context windows: 256K vs 256K tokens. Compare their real outputs side by side below.
Horizon Beta is made by openrouter while xAI: Grok 4 is from xai. Horizon Beta has a 256K token context window compared to xAI: Grok 4's 256K. On pricing, Horizon Beta costs $0/M input tokens vs $3/M for xAI: Grok 4. In community voting, In 9 community votes, Horizon Beta wins 88% of head-to-head duels.
In 9 community votes, Horizon Beta wins 88% of head-to-head duels. Horizon Beta leads in Web Design. Based on blind community voting from the Rival open dataset of 9+ human preference judgments for this pair.
Pick Horizon Beta. In 9 blind votes, Horizon Beta wins 88% of the time. That's not luck.
Horizon Beta particularly excels in Web Design.
xAI: Grok 4 uses 267.9x more bold
Ask them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.

Compare Horizon Beta by OpenRouter against xAI: Grok 4 by xAI, in 9 community votes, horizon beta wins 88% of head-to-head duels, context windows of 256K vs 256K, tested across 40 shared challenges. Updated April 2026.
Horizon Beta is the better choice overall, winning 88% of 9 blind community votes on Rival. Horizon Beta costs $0/M input tokens vs $3/M for xAI: Grok 4. Context windows: 256K vs 256K tokens. Compare their real outputs side by side below.
Horizon Beta is made by openrouter while xAI: Grok 4 is from xai. Horizon Beta has a 256K token context window compared to xAI: Grok 4's 256K. On pricing, Horizon Beta costs $0/M input tokens vs $3/M for xAI: Grok 4. In community voting, In 9 community votes, Horizon Beta wins 88% of head-to-head duels.
In 9 community votes, Horizon Beta wins 88% of head-to-head duels. Horizon Beta leads in Web Design. Based on blind community voting from the Rival open dataset of 9+ human preference judgments for this pair.
Pick Horizon Beta. In 9 blind votes, Horizon Beta wins 88% of the time. That's not luck.
Horizon Beta particularly excels in Web Design.
xAI: Grok 4 uses 267.9x more bold
Ask them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.

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40 fights queued
28+ more head-to-head results. Free. Not a trick.
Free account. No card required. By continuing, you agree to Rival's Terms and Privacy Policy