[tychver]

This was probably true 10 years ago, but these days it's basically FUD. Since then Ruby improved performance something like 5-80x from 1.8 to 2.5 and moved from an interpreted language to a VM nearly as fast as LuaJIT. Go only has 3-5x the throughput for tasks like: grab 100 rows from PostgreSQL, serialize to JSON, respond via HTTP. Lots of the hot code in Ruby around fetching rows from the DB, serializing to JSON, and HTTP parsing have also since been implemented as native functions in C, massively improving performance with zero effort required by the developer.

[merb]

yeah this is cool, until you make a single map...

[tychver]

Do you mean: "take a few thousand rows and map them to a different data structure"? Because I benchmarked that recently and mapping 16,000 rows of GPS points using haversine distance in pure Ruby takes about 12ms, and about 5ms in Go. It's not that much slower. There are tasks where Ruby can be ~100x slower than Go, but a simple map isn't one of them.