OpenAI: GPT-5.2 wins on more metrics (5 of 9), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | Inception: Mercury 2 | OpenAI: GPT-5.2 |
|---|---|---|
| Intelligence Index | 32.8 | 46.6✓ |
| Coding Index | 30.6 | 44.2✓ |
| GPQA Diamond | 77% | 86%✓ |
| Design Arena Elo | — | 1264✓ |
| Speed (tokens/sec) | 476✓ | 47 |
| Latency | 253ms✓ | 1.3s |
| Input price /M | $0.250✓ | $1.75 |
| Output price /M | $0.750✓ | $14.00 |
| Context window | 128K | 400K✓ |
| Capabilities | ReasoningToolsJSON | ReasoningToolsJSONVision |