Disclaimer: I am a founding editor of one of the journals listed here.
In the field of computational geometry, there are four specialized journals, that I would rank in this order:
- Discrete & Computational GeometryDiscrete & Computational Geometry (DCG) - Wikipedia
- Journal of Computational GeometryJournal of Computational Geometry (JoCG) - Wikipedia
- Computational Geometry: Theory and ApplicationsComputational Geometry: Theory and Applications (CGTA) - Wikipedia
- International Journal of Computational Geometry and ApplicationsInternational Journal of Computational Geometry and Applications (IJCGA) - Wikipedia
I don't think anyone who works in the field would dispute the relative rankings of DCG, CGTA, and IJCGA.
JoCG is another story. It's a relatively new open-access journal, established in 2009. I place it second here because I think that's a fair estimate of how good a paper has to be in order to get accepted in JoCG. If you measure quality in other ways, you may rate it differently.