nelylI have the Q701 currently and its never been an issue. I used them as my primary headphone for many years and they always stayed put. The clamping force isn't very high but the headphones are light and with the fuzzy earpads there was always plenty of friction. They obviously won't work if you are going for a run but normal usage they are great! If you are going to take them out of the house make sure you buy a decent quality headphone amp though as an iPhone on full blast isn't really enough.
nelylYou're not going to want to wear these travelling. They sit really lightly on the head, and they are open back, so it's going to bleed like crazy to those around you and let in a ton of ambient noise.