I switched to Unity from Unreal Engine for the ocean technology. Unreal Engine does not have forward rendering and as such, oceans with transparent water are not possible without transparency sorting issues. There is the old technique called depth testing that renders an opaque version of the ocean on top of the transparent one to get depth info and then everything behind the first wave is discarded and masked with heavy blur to avoid artifacts, but it is too much of an compromise when Unity comes mouth-ready with oceans. No problem, Unity and UE4 essentially do the same things and hopping between engines for their individual strengths is actually fun. They should honestly just join forces and merge. UE4 was better for the last physics based project, Unity now for the oceans. I still wish Unity had UE4's in-built distance fields for foam generation.
Big waves with fast boats and submarines in Unity3D so far