Codex is pretty good, OpenAI models are up there with Anthropic's, though I still prefer the latter for most development tasks (in part UI/UX, in part personal preference for how the model performs and interacts with me and the codebases). That said, if you do get a subscription from OpenAI, they actually have more generous usage limits than Anthropic - Anthropic's Pro tier is borderline useless for agentic development and I just went with their 100 USD Max tier instead. OpenAI might be more cost effective, though GPT-5.5 is more expensive than GPT-5.4, for example.

I'm recently also considering downgrading to Pro and using DeepSeek V4 Pro for anything but the more complex tasks and basically wrote a little utility to hook Claude Code up with 3rd party providers better: https://ccode.kronis.dev/ or tbh I could also just use OpenCode on the CLI or maybe something like KiloCode in Visual Studio Code (sadly RooCode got retired, liked their UI/UX a lot too).

I guess where I'm going with all this is that most of the SOTA or near-SOTA models are pretty okay and if you want, you should either get their more affordable plans for a month and experiment, or maybe hook up whatever tools you have with something like OpenRouter and try out a bunch of them: https://openrouter.ai/ (though some of their providers quantize the models a lot, look out for that) Personally I'd also add the new Kimi and GLM models to the list of the ones to try out.

Paying for API tokens isn't really financially good long term for anyone but companies and eventually most folks just settle on a subscription of some sort, since those are heavily subsidized and more cost effective.