I had the original in-ear beats when they first came out, and I was very unimpressed. Sound quality was decent, but decent doesn't cut it for $150 headphones. The bass was way too prevalent and mids were practically nonexistent. Quality over all sucked too, like comparable to Apple's $30 earbuds.
Since then I've always used the Apple earbuds. They suck, but I honestly can't see spending ~$100 for in-ear headphones. The sound is never as good as similarly priced on-ear or around-ear headphones. That's just me though.
I can't speak for their in-ear headphones, but I've owned a pair of Sennheiser on-ear headphones for a few years now, and despite all the yanking and running over the cord with my desk chair, they still function 100%. I am astonished by how such a thin cord could survive such abuse TBH.