The big feature here is the function calls, as this is effectively a replacement for the "Tools" feature of Agents popularized by LangChain, except in theory much more efficient since it may not require an extra call to the API. In the case of LangChain which selects Tools and their functional outputs through JSON Markdown shennanigans (which often fails and causes ParsingErrors), this variant of ChatGPT appears to be finetuned for it so perhaps it'll be more reliable.
The slight price drop for ChatGPT inputs is of course welcome, since inputs are the bulk of the costs for longer conversations. A 4x context window at 2x the price is a good value too. The notes for the updated ChatGPT also say "more reliable steerability via the system message" which will also be huge if it works as advertised.
While developing a more-simple LangChain alternative (https://github.com/minimaxir/simpleaichat) I discovered a neat trick for allowing ChatGPT to select tools from a list reliably: put the list of tools into a numbered list, and force the model to return only a single number by using the logit_bias parameter: https://github.com/minimaxir/simpleaichat/blob/main/PROMPTS....
The slight price drop for ChatGPT inputs is of course welcome, since inputs are the bulk of the costs for longer conversations. A 4x context window at 2x the price is a good value too. The notes for the updated ChatGPT also say "more reliable steerability via the system message" which will also be huge if it works as advertised.