I bought these after losing my Sennheiser OMX80 Sport II.
They are VERY light and don't fit tightly and that is why they are good for running, BUT if you sprint they fall off your ears since they don't have a tight fit.
They are not good for the gym because they fall when you lie down on a bench of move the cable slighty doing shoulder press or similar.
Sound quality/volume is fine.
Overall, ideal for slow running. I would ruther recommend the Sennheiser OMX80 Sport II which I have just bought again and NEVER fall.