I write Python for my day job, but I often prototype in Go because it's so much easier. Also, regarding I/O, Python does nothing during I/O unless you take care to write async code and only call async libraries. Go does async by default and truly outclasses Python at IO bound tasks. For CPU bound tasks, Go is only 2 orders of magnitude faster. For I/O bound tasks, Go is about 4-6 orders of magnitude faster unless Python is carefully optimized.