In England, Wales and Northern Ireland, the General Certificate of Secondary Education (GCSE) has been for the last 35 years the most common qualification by which students' attainment at age 16 has been measured. The range and balance of processes by which the GCSEs' programmes of study have been assessed have varied over the decades, to include both teacher-assessed coursework and modular or end-of-programme timed written assessments (examinations). The necessary replacement in 2020 of GCSE written examinations with teacher-led assessment provided a unique opportunity to explore students' perceptions of the validity and utility of both examination and teacher-led assessment media for this high-stakes award. This research reports part of a survey that explored the experiences of GCSE candidates in 2020, with particular focus upon students' perceptions of preparing for written examinations, and then for teacher-led assessment. 216 students responded to a mixed quantitative/qualitative methods survey that invited opinion and reflection on the relative affordances and shortcomings of written examinations and teacher-led assessment, both for the individual respondent and the wider student cohort. Responses revealed a balance of both positive and negative evaluations of both assessment media, with an almost equal preference for either, albeit many respondents indicated consideration of some other assessment medium (e.g. modular assessment; combined assessment media). We re-emphasise the attested value of ongoing 'dialogue' and consultation with student stakeholders to inform planning for optimisation of assessment utility and validity.