As someone writing my first meaningful react app, code quality from gpt4 is monstrously better than 3.5. With gpt 4 i can often paste entire components and get meaningful corrections/bug fixes/non-trivial refactors. 3.5 just does a loop of mistaken fixes while it runs out of context length.
There's a massive difference in response quality in my experience.
For example, I asked 3.5 to find a bug in a lengthy piece of Javascript. It said it's hard to give a correct answer because it doesn't know what the HTML or CSS looks like.
GPT4 spotted the bug almost immediately (it didn't manage to fix it though).
One area where I noticed Bard was clearly behind (at least without crafting a better prompt) is getting from half-working program to a running program then sometime even to a correct program (I was using Python).
With GPT 3.5 and 4, I was able to just paste in the error and it'd do the rest. Bard however tried to tell me what the error could be, and wouldn't do well even when asked to fix the code.
Even GPT 4 though, when asked to go from specs to tests + code, would get stuck in a loop of making one test pass only to make the other pass and vice versa.
The program I tried to let it write was a query validator that can test whether a string matches a pattern that uses AND, OR and NOT.
It did well on parsing my specs into tests, but from there on it didn't go very well.
We don't know (both for previous model LaMDA and new model PaLM 2), but it is less important for Bard because Bard has access to live data from Google search.
