I had Shure SE210, predecessor of SE215, and I currently have Sennheiser PX200-II. The Shures were very isolating with the foam sleeves, certainly more than the Sennheisers are. The Shures lasted a long time, nearly five years of frequent and strenuous use. They had a very thick cable and strong round plastic case. Note: you will need to replace the foam sleeves at least once a year, so budget for that.
There are some differences between SE210 & SE215, and I am unfamiliar with SE215. This review might help: http://www.innerfidelity.com/content/shure-ear-series-se215-se315-se425-and-se535. Mike at Headfonia adds, "It comes in translucent black shell or a clear shell. From experience, we tend to stay away from the clear shell version as it doesn’t age as well as the black." Link: http://www.headfonia.com/in-ears-headphone-recommendations/. I have a fairly high opinion of all the Shure headphones I've used, both the build and the sound.