I’m currently in the processes of adopting Julia, and my background is Modern Fortran. I would say that the main allure of Julia for me is the promise of a smoother workflow, especially in potential collaborations. The Julia ecosystem also seems to be much faster at adapting than Fortran, which I guess is due to the completely different philosophies - no Fortran change will ever break old code and “there’s no need to fix what isn’t broken”. Though it simply amazes me that I managed to run into multiple issues with Fortran Coarrays (at least with the compiler I used), for example, which have been in the language longer than Julia existed. It feels like there is just not enough demand for the Fortran 2008+ features in our community for them to be truly stable (and I used one of the bigger compilers). Again, this is just my own experience.
And as other people in the thread have already mentioned, you have a lot of boilerplate with Fortran. I have had cases where I had to write what is essentially the same code multiple times because I wanted to handle multiple array ranks. While there are testing frameworks out there for Fortran, they can be problematic to set up, and I don’t think I’ve seen any Fortran projects using CI.
Those are the main reasons I’m trying out the switch, but as you can see, those are personal and also project-dependent. If I were stuck working with a large existing Fortran codebase and didn’t want to use the newest quality-of-life features, I don’t think I would switch.