My own experience has definitively been frustrating at times. I think the main issue is the lack of consistency and breakage between the different libraries/languages. Even minor version could cause issues when trying to create gRPC message definitions for different languages.

The documentation was also lacking when it came to arguments for each of the libraries.

I vaguely remembered wanted to change a small piece of a message and it took me a whole day of spelunking to figure out how to do it, browsing C++, Go codebases.

Take this with a grain of salt, this was a few years ago and things might have changed.