Nearly half (45 per cent) of 5,700 sixth-formers surveyed by ELWa, the post-16 education funding agency, said they were "extremely or very" satisfied with their learning experience. Only 6 per cent were dissatisfied.
But a much higher proportion of students in colleges and workplaces - around seven in 10 - are "extremely or very" satisfied with their courses, according to a separate survey of more than 6,000, carried out earlier this year.
Satisfaction levels were higher among sixth-formers in Welsh-medium schools (51 per cent) and those living outside south-east Wales.
Most sixth-formers got both their first choice of subjects and of learning provider. But a substantial minority of sixth-formers had not considered going anywhere besides their school to continue their studies.
In fact, 85 per cent said the reason for choosing the sixth form was that they were already attending the school.
Among those who did not get their first-choice subjects, a third said schools had not run them while 45 per cent faced timetable clashes.
Around half were "extremely or very" satisfied with the teaching they received. But in focus groups, some pupils said teachers were "too ready to fall back on sarcasm and humiliation when some students were struggling".