Can someone recommend a good viewer for point clouds?

edit

Have you try in viz :

| Help:
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          p, P   : switch to a point-based representation
          w, W   : switch to a wireframe-based representation (where available)
          s, S   : switch to a surface-based representation (where available)

          j, J   : take a .PNG snapshot of the current window view
          k, K   : export scene to Wavefront .obj format
    ALT + k, K   : export scene to VRML format
          c, C   : display current camera/window parameters
          F5     : enable/disable fly mode (changes control style)

          e, E   : exit the interactor
          q, Q   : stop and call VTK's TerminateApp

           +/-   : increment/decrement overall point size
     +/- [+ ALT] : zoom in/out

    r, R [+ ALT] : reset camera [to viewpoint = {0, 0, 0} -> center_{x, y, z}]

    ALT + s, S   : turn stereo mode on/off
    ALT + f, F   : switch between maximized window mode and original size

You can use mouse with right and left button and wheel with alt shift and ctrl modifier too..