I personally use Opus 4.6 for my projects. This is Anthropic's flagship model that genuinely thinks before it answers. Opus 4 and Sonnet 4 are the workhorses - Opus for when you need deep reasoning and maximum quality, Sonnet for everyday tasks where speed matters more. But with Claude you'll have to pay more for that high quality, so to work properly here you need the Max plan starting from $100+/month.