Sennheiser has crafted a very successful line of in-ears with the IE-line. The IE7s are no exception, with an incredibly big sound stage and musical presentation they are a winner. My main beef with the IE7s is the sharp edge of the ear piece. It is located so that it most likely will conflict your ear if you are not careful. I have fairly large ears and even so if I was not cautious while inserting them I could get them to feel annoying in my ears. The foam tips supplied with the IE7s are of a really good quality and make for a comfortable listening experience.
Sound quality wise the IE7 model is a tiger leap forward compared to the IE6 which are alright for the price. The IE7s are just so much more entertaining to listen to and in the long run I think you will find it a good investment if you like the rather distinct Sennheiser house sound.