My experience as well. Working in Scala primarily, it tends to be very good at following the constructs of the project.

Using a specific Monad-transformer regularly? It'll use that pattern, and often very well, handling all the wrapping and unwrapping needed to move data types about (at least well enough that the odd case it misses some wrapping/unwrapping is easy to spot and manage).

A custom GPT or GEM with the same source files, and those models regularly fail to maintain style and context, often suggesting solutions that might be fine in isolation but make little sense in the context of a larger codebase. It's almost like they never reliably refer to the code included in the project/GPT/GEM.

Claude on the other hand is so consistent about referring to existing artifacts that, as you approach the limit of project size (which is admittedly small) you can use up your entire 5-hour block of credits with just a few back-and-forths.

I did try it yet for more than a week still 4o still pretty much better in terms of python coding and architecture/documentation design

Really interesting, I used it today still lots of issues. Maybe my python notebook is not approach is too complicated for Sonnet? Couldn't be able to fix a custom complex seaborn plot. 4o failed too. o3-mini-high managed to do it really well on the other hand.