The biggest problem is it's not as well maintained as core Ruby is and working with it is highly quirky to put it mildly. There's a handful of people that know

The biggest problem is it's not as well maintained as core Ruby is and working with it is highly quirky to put it mildly. There's a handful of people that know how to write proper event-driven Ruby code and many of these are not actively involved in the EventMachine world any longer. It's basically a thin Ruby wrapper around libevent and isn't nearly as neat and tidy as something like Node.js is by comparison. There's also a lot of long-standing animosity towards it. Example: http://www.slideshare.net/KyleDrake/hybrid-concurrency-patterns http://www.slideshare.net/KyleDrake/hybrid-concurrency-patte...