Vortex works the best in Cycles, Eevee is not officially supported. Using Eevee might be possible in some specific cases, but not all features work and it is significantly less stable.

Vortex Flow works with Mantaflow, an incredibly powerful FLIP fluid solver. Since Blender 2.8, this is the standard engine used for fluid simulations, so everyone has acces to it. No addons or installs required.
It also works with FLIP Fluids in Blender 2.93.

No, although it is the first of its kind to get correct looking, animated detail on simulations, the shaders can also be used on normal meshes.  Animating normal meshes can be done with a constant flow or wind direction, or a custom flow map texture.