I had been on the pro plan for a few months and recently upgraded to the $200.00 AI Ultra plan because I've gotten good mileage out of 3.8 flash while keeping in mind that it's far from perfect. Argon is better in my experience in terms of reliability (especially in not claiming to have done things it clearly didn't) but I have to agree with the hallucination part, for a "SOTA" model (before Carbon came out at least), it hallucinates significantly more even on moderately complex tasks compared to Astra or Opus while being much slower than 3.8 flash (as expected of course). Another irritating thing is that like the 3.6+ models (but thankfully less often), it has a nasty habit of sometimes recognizing unstaged changes in the branch as not being its own work (whether done manually or with another agent) and deciding to undo them or even delete files. That's something I don't expect any SOTA model to do without at least asking the user.

Gemini so far has also had terrible computer-use capability or tool-use capability compared to ChatGPT (haven't used enough of Claude for these tasks lately to really compare). I tell ChatGPT to make some formatting changes to a LaTeX file I gave it and generate a PDF, it get's the PDF generated most of the time; occasionally the download link doesn't work, but that seems to be a server or link-generation issue, the actual PDF is generated and it quickly fixes the broken link when told. With Gemini, it's a long struggle and I use LLMs for formatting LaTeX a lot, so sometimes if ChatGPT is doing some long-running task for me, I have to begrudgingly give the document formatting task to Gemini, and it's dreadful every single time.

Before Argon was a thing, it once generated a PDF file, then started claiming PDF generation was not part of its functionality and the link that was previously working stopped doing so. I think I had inadvertently jail-broken a functionality because it refused to generate PDFs again and said the first time was a mistake. With Argon, it doesn't deny having the capability, but it takes much longer than ChatGPT, and messes up more formatting than it fixes. Its PDF viewer is also trash and seems like it gets built from scratch every time you want to view a PDF.