Godot is nowhere close to Unity in terms of 3d it's like years behind.
But is it "good enough" to convince some people to use it instead?
For the moment the best it can do is to provide an (ever improving) basic alternative to Unity that forces them (and the market in General) to not be greedy and careless.
This is probably good for the game engine market as a whole.
- The renderers are fundamentally different. Godot has advertised their rendering to not be as flexible while Unity throw you some weird shader language that lets you do whatever you want. There's a lot of jank in Unity's renderers but they are still more mature than Godot.
- Physics is a huge weakness of Godot and Unity has options to either use their much more mature built-in physics or Havok (IIRC).
to name a few technical comparisions. Godot still has a way to go before being comparable with Unity in regards to 3D.