GlenRIf you already have custom earphones you will know the difference. If you haven't make sure that these fit your ears snugly. CIEM's are the best for people who can't find a good seal on universals and have a more comfortable wear. I personally had CIEM's from ultimate ears. While I did enjoy them, it kinda sucks not having to be able to share the quality. My ears are molded quite well to noble audio universals to a point where there is full suction and I can run with them without it slipping or falling out. ( I use the red tips always) Obviously if your ears don't fit that well on noble universal lines, i'd recommend you go for CIEMS.
Worst case scenero, buy it and resell it on any high end audio forum. Don't take me granted, but I personally think you can resell easily at 900 again. ( Me being a 4 year member in head-fi and an avid audiophile)