I wouldn’t say Sonnet costs more for no reason. I’ve been using GPT, Sonnet, Deepseek, Kimi K2, and a few other models. My experience, having used GPT-5 a lot since it was introduced, is that Sonnet is still a better model.
Despite the improvements with GPT-5, over the last two days I discovered that it is making some BAD code edits. One example: dynamic TS imports, to import a type that was already imported at the top of a file, inside of a Promise<T> generic, as the return type of a function….
someMethod(…): Promise<(await import(‘./path’).SomeType> { … }
I mean, WAT!?!?! I found my code from the last couple of days RIDDLED with that kind of thing, as well as a whole slough of other small issues, that all added up to code that did not do what it was supposed to, and caused runtime errors. Other examples of just bad code…frequent casting of things as any. I even had a ton of `(this as any)?.blah?.blah?.()`when the service being used was already injected, was always a real instance, and worked perfectly fine: this.blah.blah() would have been perfectly fine! Countless cases of ROGUE unknown as something casts, because GPT-5 insisted that it was working around typescript assignment restrictions…which…WHY?!?!?!? Thats WHY WE USE TYPESCRIPT!! Don’t bypass the type checker, dimwit!!
Attempts to use GPT-5 to resolve these issues, resulted in each of them becoming even more complex and convoluted, weird, and causing even worse runtime issues.
Sonnet, though? Psh, no problem. Cleaned it all up right away, produced beautiful code, didn’t introduce any more weirdness, and I was able to move on with my day.
Interesting thing about cost… GPT-5 may be half the cost, per MTok wise, but between time lost waiting on the LONG thinking cycles (same problem with Gemini 2.5 as well), then time lost with non-functioning code, then further time lost fixing broken code, then more time lost dealing with WORSE issues due to bad fixes, then MORE time lost…either fixing it yourself (which I did do some of yesterday, just to wrap my head around what the heck was going on and why) or switching to another (more expensive, at least on a per MTok basis) to fix the issues, etc. etc.
The interesting thing about cost, is, its not so much about Sonnet’s higher MTok cost. I’m far more expensive than Sonnet. The WASTE OF MY TIME, wastes the time and money of the company I am working for. Further, when you burn time and tokens FIXING what a model of lesser quality BROKE, you ultimately burn your “it costs half as much” buffer, AND THEN SOME, and quite likely end up in the inverse situation: GPT-5 + screwups + screwup fixes + screwups of screwup fixes + manual fixing of all the screwups…your total token cost is more like 4x that of Sonnet, which usually (at least IME, speaking for myself) gets things right in one go.
And again, I am WAY more expensive, than the model or MTok cost. So when MY time is wasted by a model? Its significantly more expensive than even what I mentioned above. Don’t dismiss Sonnet just because its MTok cost is higher. What do YOU cost, and what do model screwups cost in terms of YOU and your billable time???