We have a couple of Audio Techica M series In-Ear Wireless systems. We've both got through two sets of their earpices - these are not cheap either. This time around we've both dipped for Westone UM3X in-ear monitors. While not cheap at about $400 they have three drivers and are truly full range. I used to hear the bass from the PA subs but no more - with these stuffed in you get the real dynamics the people are hearing. One nifty thing the Presonus does is you can allocate 2 channels to your IEMs and with the ATs in stereo, utilise the pan and level to set up a stereo listening field in your head. This is SO useful - the click is way out on my right and my stereo guitar effects are in stereo along with the stems. Another cool thing about the Westones is that you can just unplug the cable from teh earpiece - no returning to factory for new wir.