I didn’t see either Kong or Apes, but based on images, trailers, and clips I’ve seen in various parts of the web, I would say Apes has the better vfx.
They’re pretty close really. I just feel that Kong has more impressive shots. There wasn’t a moment when I didn’t believe I was really seeing these gigantic creatures. Apes looked great, of course, it just didn’t have the awe inspiring shots that Kong was full of.
Opinions, of course.