I have a basic toon-style material I'm using for the windows on a car here. I'm using Eevee and used nothing but a layer weight and colorramp to achieve this. However, I get these weird jagged lines along the edges when I use Eevee. This (mostly) goes away with cycles.
The problem is that i can't use cycles because other materials on the car use the shader to RGB node which isn't available in cycles, so I have to use Eevee.