GPT-5.4-Cyber (OpenAI) vs Grammarly

Grammarly edges out GPT-5.4-Cyber (OpenAI) by 0.8 points (8.0 vs 7.2) -- a A-tier vs B-tier split that's narrow but real. Not a blowout; both belong on a shortlist. The score gap shows up most clearly in the categories that matter for Grammarly's strengths, so if those categories are your priority, the lead translates.

On pricing, Grammarly starts free while GPT-5.4-Cyber (OpenAI) requires a paid plan from day one (Not publicly disclosed+). If you're testing the waters or running an occasional workload, that gap matters more than the score differential. GPT-5.4-Cyber (OpenAI) starts at Not publicly disclosed; Grammarly starts at $0. Compare what each entry tier actually unlocks before you compare list prices -- the limits matter more than the headline number.

By use case: pick GPT-5.4-Cyber (OpenAI) when enterprise soc teams, established security research orgs, and vetted individual defenders who can qualify for trusted access for cyber. Pick Grammarly when non-native english speakers, professionals who write lots of emails, and anyone who wants a passive grammar net running in the background. The two tools aren't fighting for the same person -- they're aiming at adjacent jobs that occasionally overlap. If you're squarely in Grammarly's lane, the tier-list ranking and the use-case fit point the same direction; if you're in GPT-5.4-Cyber (OpenAI)'s lane, the score gap matters less than the fit.

Bottom line: Grammarly is the safer default for most readers, but GPT-5.4-Cyber (OpenAI) is competitive enough that the tie-breaker is your specific workload, not the spec sheet.