Any experience out there with these two: Ultimate Ears super.fi 3 Studio or Sennheiser CX300?

I want buds/in ear to replace the ipod phones. Something portable and comfortable, with good sound. I often stick the ipod(shuffle) and buds in my pocket. This has caused the rubber part around the buds to come off. The new ones I get should have a protective case or be designed to be durable going in and out of my pocket.