Planio, which is based on Redmine, relies in terms of communication on blog entries, discussion forums, comments. There's also team chat available in the pro version, but it's not as deeply connected to projects as in Stackfield.
Stackfield additionally offers a team chat for each work area in order to keep the exchange all topic related. The communication stream will also show you all activities from other modules within this room, so you can directly comment on them without opening a new window or work space.
Although Redmine / Planio offers a comprehensive system for task management, it's mainly developed for the Agile method. For example, you cannot adapt the Kanban Board to other processes.
Of course you can also choose between different task views on Stackfield, e.g. Kanban Boards or Gantt Charts. But you are also able to individually define certain parameters, such as statuses. Hence, Stackfield is not only suitable for the IT department, but also for your marketing, sales and design team. Define your own workflows with just a few clicks.
The work on Stackfield takes place in rooms within an organization, which can be either for the entire company or for a department. You can add employees to this organization and assigned them a rights group in just one step. As person leaves the company, you can remove the user from all work areas / rooms with one click.
Additionally, you can create fine-grained authorization groups within the single rooms, so you know at any time who has access to the data you share in there!
Stackfield feels lighter and is easier to understand right from the start. All users of the tool benefit from that, both team members and administrators. This ease of use also allows different teams to use the tool together.
Moreover, on Stackfield, unlike Redmine or Planio, all relevant data are encrypted directly on the device of the user and securely stored on our servers in Germany. For more information about Stackfield security, please visit the following page: https://www.stackfield.com/security.
In addition, Stackfield does not require its own servers, maintenance, or installation when used in the cloud, making it a true Redmine alternative for small and large companies! (But there's also a self-hosted version available!)