If you want convenience first: hosted tools may feel easier in week one, but usually become limiting once you need custom workflows, cost control, and permission boundaries.
If you want real operational control: self-hosted and open-source options become more attractive because they let you shape channels, tools, monitoring, and future extensions around your own setup.
If your assistant can act: evaluation must include tooling, security, logging, and maintenance, not just prompt quality or conversation polish.
If the team is small: the winning option is usually the one that can start narrow, stay controllable, and expand without forcing a rebuild.