When choosing project management software, consider the needs of both internal and external team members. A tool should facilitate communication, have reliable notification systems, an intuitive user experience, granular permissions levels, and a price that won't break the bank. External team members may not be as picky about learning new software if it's relatively straightforward and necessary for their work, and they may prefer to use tools of their choice instead of integrating with your app. A streamlined communication capability is essential, allowing users to comment on tasks, tag members, and get emails that take them directly to the comment in question. Reliable notification systems are also crucial, as some apps may not send notifications for new assignments or comments, or have issues with notifications when team members are "away". An intuitive user experience is vital, as freelancers won't want to spend time learning a tool, and granular permissions levels allow you to share specific information with external workers. A price that accommodates multiple users without breaking the bank is also essential. Ultimately, asking the external team members for their input can help you find a suitable tool.