Yes, I've used it extensively. It works pretty well, although it has quirks around the JSON format (probably because they're using XML and some library that does a weird job converting it), so it will do things like return the literal string `"null"` and if you have one open order, return `"orders": {}` but if you have multiple that becomes an array, so just little inconsistencies like that. The documentation is adequate, not great.
It is much less cumbersome and finicky than the IBKR TWS API.