Opening a Revit 2013 file with PCG clouds in Revit 2014...

This is basically what will happen:

So, basically you can choose to re-index to RCP, or leave them as-is and continue to use the PCG.

While there is much to love about the smooth performance RCP point clouds, I have to admit that PCG point clouds seemed to allow:

• greater point density, perhaps due to different default indexing settings, 
• more consistent display (ie. once the view had regenerated, that's how it would stay - while RCP seems to slowly and continuously re-gen until you get a very realistic view)
• and didn't have cropping problems - I've noticed that a 3D Section Box with an RCP point cloud will require a greater "buffer" than with PCG.  If you crop it too close, the RCP points won't show (even if they physically exist in that section box space).