I recently had a disappointing experience with Useberry. After launching a study through Useberry powered by Prolific, I discovered that I could neither reject nor approve participants' submissions directly—features that are readily available on Prolific itself. Additionally, Useberry does not support participant screening questions, further limiting control over the quality of participant responses. Despite reaching out to their support, the available solutions—using custom blocklists or allowlists for future studies—didn't resolve my immediate issue. Overall, this lack of flexibility was frustrating, particularly as it relies on a third-party service that inherently supports these essential participant management options.