During their doctoral studies, students undergo an emotionally and intellectually intensive process involving a wide range of positive and negative experiences. This article analyses PhD students' perceptions of the most positive and negative experiences related to doctoral study conditions. Previous researchers have primarily focused on analysing experiences that negatively affect doctoral work and have related these experiences to institutional, social and individual variables. However, little is known regarding positive experiences and how both positive and negative experiences are interpreted and related to variables connected with doctoral study, such as discipline, funding, enrolment type, and the stage of the doctoral process. In total, 1173 doctoral students from 56 Spanish universities completed an open-ended online survey. The findings indicate that opportunities for PhD students to communicate their scientific advances, receive expert feedback and interact with other researchers have a high positive influence on their doctoral journey. However, funding difficulties, particularly for students in the social sciences, and relationships with the research community, principally with the supervisor, were perceived as the main negative challenges. Experiences related to research design, data collection and analysis were perceived either negatively -- primarily for mid-level students -- or positively. These results should be considered in future doctoral programme policies to determine when, how and why to provide specific support during the doctoral process.