This article presents a study with a twofold research aim: (a) to ascertain university students' perceptions on two combined assessment tools (e-portfolios and formative rubrics) and (b) to identify if among students there were differing perceptions on the use of e-portfolios, and what factors favored acceptance of these. The data gathering method was a questionnaire administered to 247 students on the Education Degree at the University of Barcelona. Regarding our first aim, it was confirmed that although the portfolio and rubrics were used in combination, students viewed each of them independently. Regarding the second aim, we identified four groups and a range of factors that may explain the varying perceptions of the portfolios and rubrics. Favorable factors were, in first place, greater teacher experience in using the digital portfolios; second, continuous technical support for their use; third, their having greater weight in assessment; and fourth, smaller class sizes.