One-to-one computing programmes -- that is, when each student has a personal, portable computer to use while learning -- have been studied extensively, mostly regarding their actual classroom implementation. In this quantitative study, the authors take a broader perspective, exploring the impact of teaching in one-to-one computing programmes on teachers' beliefs regarding their job outside the classroom. Participants were middle school and high school teachers who had taught in both one-to-one and traditional classrooms -- and hence could reflect upon the differences between the two settings. The methodology included questionnaires based on Danielson's comprehensive Framework of Teaching. The results suggest more positive attitudes towards teaching in one-to-one programmes than in traditional classrooms in all domains tested; however, the one-to-one instruction applied portrays a rather shallow, instrumental use of the digital devices in a way that supports existing teaching practices and beliefs, rather than a transformative effect of such programmes on teaching.