OpenAI: GPT-5.5

GPT-5.5, released by OpenAI in April 2026, is positioned as a frontier model for complex professional workloads, featuring a substantial 1M+ token context length. It performs among the fastest models, ranking in the top tier for speed (61st percentile across 8 benchmarks). However, it tends to be positioned at premium pricing levels, ranking in the 9th percentile for cost. A standout characteristic is its exceptional reliability, demonstrating a 100% success rate across all benchmarks, indicating minimal technical failures. The model exhibits remarkable accuracy in several critical areas. It achieved perfect scores in General Knowledge, Reasoning, and Ethics, with the latter two also being highlighted as the most accurate models at their respective price points and speeds. Its Instruction Following and Coding capabilities are also very strong, scoring 88% (95th percentile) and 95% (90th percentile) respectively. While its Hallucinations score of 96% is solid, it's not a top-tier performance. Email Classification and Mathematics show strong, though not perfect, accuracy at 98% and 93% respectively. Overall, GPT-5.5's key strengths lie in its robust reasoning, ethical understanding, and general knowledge, making it highly reliable for demanding tasks despite its premium cost.