Claude Sonnet 3."6" may be limited in rare situations, but its personality really makes the responses outperform everything else when you're trying to take a deep dive into a subject where you previously knew nothing.
I think that the "thinking" part is a fiction, but it would be pretty cool if it gave you the thought process, and you could edit it. Often with these reasoning models like DeepSeek R1, the overview of the research strategy is nuts for the problem domain.