JBoss.org: Netty - Performance Comparison of Apache MINA and JBoss Netty
"One of my big complaints with Apache MINA is the high latency that’s incurred when sending data. MINA uses a set of I/O threads to handle reads and writes. This is typical of many non-blocking I/O frameworks.
Netty is much more clever than MINA. In Netty, when you make a call to send data and the send queue is empty, Netty will just send the data. We are using non-blocking I/O so the call will still be asynchronous. If the send queue is not empty, Netty will queue up the data to be sent in much the same way that MINA does sends. The Netty approach is much faster."