[nevcairiel]

The old ReplayGain reference would be around -18 LUFS (which is -18 dBFS), 5dB louder than the -23 LUFS EBU R128 reference.
And its a good thing that its lower too, since RG didn't always manage to create a uniform volume level since some tracks would clip otherwise, which should be a much rarer problem with the EBU R128 reference.

The biggest advantage of EBU R128 over RG is however proper and official support for multi-channel, which makes it actually usable for video.