Depends on what you're doing. I read that article a couple years ago and thought "Take that you libevent C zealots." And while I still firmly believe that the JVM is optimized and mature enough to hold its own against platforms that have traditionally been considered faster, I still think there are cases where event-based I/O will out-perform thread-per-request. For instance, if most of what you're doing is shuttling bytes back and forth (like in a proxy). I also wouldn't be surprised if a thread-per-request app took a bigger hit when virtualized (like EC2) than an event-based app.