I have recently written a quite complex application with Dancer2, and can vouch for its effectiveness. The documentation is very well laid out and easy to follow, and like Mojo, it takes only a few minutes to stand up your first application to get you started by following said fine documentation. The devs are very responsive via many mediums, and has a very large community when one has questions. I have only "played" with mojo very briefly, then decided on Dancer.

I don't remember the reasons why I went with Dancer now, but I do know that it wasn't based on any negative experiences I had with mojo. Probably because I tried it after mojo, and just kept coding.