I've been using Formula Foundry in Google Sheets for a few months now. I work in project management and use spreadsheets on a daily basis.
The default formula field in Google Sheets is fine for short formulas but not for advanced ones which I have a lot. Formula Foundry made it much easier. I have initially been looking for just a formula code editor with larger window and code formatting, but I found more useful features with this product, e.g. the formula builder for those who are less familiar with programming, auto-formatting, and an integrated AI agent. I no longer need to copy-paste my formulas to ChatGPT, the chat is already there and ready to work for me.
The company also listens to its users. They implemented a bunch of improvements on the community feedback, including some of the features I asked for.
If you are an Excel or Google Sheets user, give it a try. It improved my workflow.