HTTP adaptive steaming (HAS) is becoming ubiquitous as a reliable method of delivering video content over the open Internet to a variety of devices from personal computers (PCs), to tablets, game consoles, and smartphones. HAS is able to adapt to both the available bandwidth and the display requirements by trading-off video quality. This paper describes two experiments to test end user subjective response to this varying quality. First, we tested three commercially available HAS products in our viewing room. This allowed us to control the introduction of network impairments and to record the mean opinion score (MOS). In a second experiment, we generated clips with impairments typical of HAS. These were downloaded and commented on by a group of young people. This provided insight into the response of users to different types of visual impairments and hence what steps can be taken to improve the end user experience. © 2012 Alcatel-Lucent.