Disclaimer, I tried Dancer2—well, Dancer—early on and didn’t like it and the only time I went back since v2 to look again—from a problem/question posted here—I saw code that I thought was… smelly, so stopped again without retrying. Plenty of good hackers like it so don’t discount it merely on my experience. That said, I am extremely experienced. :P I’ve written three blog platforms and two of my own webframeworks.
Mojo is a full toolset. Its testing and content parsing in particular are deeply valuable. I have still not written anything serious with Mojo because I know Catalyst and CGI.pm and naked Plack and my own nonsense well. I would almost certainly choose Mojo for a real, shared or public, project specifically because it makes test driven development semi-trivial and it is keeping up with security and new technology better than the other frameworks. It also just feels Perly, terse and DWIM. Sidenote to that, the chief architect of Mojo also created Catalyst and had one other framework between so Mojo represents a LOT of accumulated wisdom applied to the workflow of writing and maintaining web applications.