I'm using Go with Redis for various aggressive caching needs. I batter Redis and Go performs very well. A few other languages will work mostly fine for my purposes, however I like working in Go and have always had a great experience with its performance.

No traditional testing. Standard library and Redigo. That's it.

No pain points for what I'm using it for. I usually try to avoid complexity in anything I build. This is a rather simple system that is only meant to take a high volume beating, cache to Redis (content later retrieved & presented by another part of the application via another language) and be reliable.