I like that it's very customizable, so you can really make this work how your team works best! The free version has some limitations - we had to upgrade our account in order to be able use all of its features (we're paying customers).
We also wish there was more guidance when setting up new boards/teams within existing projects; sometimes things get lost along with old information over time as people move around between different tasks. If someone could help us set everything back where they belong every now & then maybe? Our biggest challenge right now isn't actually using the software itself -- but keeping track of who owns what task once everyone leaves at night. Being organized makes life easier during those times too!!