In-ear-monitors sometimes have a negative reputation, and that is not without reason. Loudspeakers are arguably the most natural way to reproduce sound, and shoving electronics into your ear is sure to create some challenges for sound reproduction. Technology has come a long way, though. If you wrote off in-ear-monitors long ago, they’re worth taking another look at!
You can read about some of the new technologies here: http://audioundone.com/in-ear-monitors-why-do-they-sound-like-that-jay-kadis-and-stephen-ambrose