Have been using this all morning for some integral-heavy math for my PhD (trying to bound certain analytically intractable integrals). It's a bit hit-or-miss. It's been able to come up with some pretty impressive bounds but also feels like more than half it does some really dumb stuff. Compared to Gemini 2.5 Pro it's pretty solid. Its thought traces are really silly though sometimes: it'll pretend to check websites or "pull out a calculator".