If you're using Soft Reflections with the Reflection Shader, then the problem is probably too low samples or too high softness. It needs very low values. Glass shader, Reflection shader, and Water shader all work similarly, and render similarly. You're not going to fix such issues by switching; if it's fixed, it's probably because a feature is no longer being used because it's not available in the other shader (e.g. soft reflections).
- Oshyan