Even though ChatGPT has captured household recognition among generative AIs, as Uber and Netflix have for ride-sharing and TV streaming, there are several worthy competitors, roughly neck and neck with ChatGPT.

Anthropic’s Claude is the most compelling apples-to-apples alternative to OpenAI’s ChatGPT I’ve come across. After releasing Claude Opus 4 on May 22, 2025, its best model at the time, Claude’s paying users have had to plod along without an update.

Until now. Anthropic finally released Opus 4.5 on November 24.

Where Opus fits in

Anthropic offers two flavors of its Claude generative AI: Sonnet and Opus. Sonnet is the one you get with the free version of Claude. It’s also among the options if you use Perplexity Pro, another generative AI I’m fond of, but which is more research-based than Claude or ChatGPT. Think of Perplexity as a research assistant, less of a chatbot than Claude or ChatGPT.

When you upgrade to Claude Pro or Max, you also get access to Claude Opus, a more powerful AI.

On those paid plans, you can still choose Sonnet for faster answers to your more straightforward queries, since it’s a more efficient and less resource-intensive AI model. When you need to pull out the big guns for a complex, multi-step task, such as coding or a complex set of instructions, then you can choose Opus.

It was a quirk of Anthropic’s leapfrog product-release style that Sonnet 4.5 came out before Opus 4.5. It didn’t make Sonnet 4.5 more capable than Opus 4 in all respects, but it did embarrass its pricier, bigger sibling in some ways.

To use Opus, you have to break out your wallet. Claude Pro costs $17 per month on an annual plan or $20 on a month-to-month plan, while Claude Max costs $100 monthly