As far as which way is better, compositing or all CG... would Jurasic Park have been as mind-blowing, if it was all animation? Or does the interaction between real-life and CG bring an extra level of "realism" to the scene as a whole. I agree that it should be whatever floats your boat... I mean, beaver. (That IS fun to write about... isn't it! ;) ) You could also look at what the Shader Pack's FakeFresnel does for looking at an angle to water. There was a thread the other day discussing it and showing an example... I forget who's it was, but it was recent. Good luck!